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Samsung

Guides for Samsung Galaxy M21

520 guides

Language & Input2

Switch Keyboard Language While Typing

Typing a message and need to jump between two languages without leaving the keyboard? On Samsung phones the space bar swipe only works once a second input language is active - with just one language enabled, nothing happens when you swipe. This mix-up between the language switcher and the keyboard settings is the usual reason the gesture seems broken.

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Notifications & Focus2

Turn Charging Sound On or Off

Every time you plug in or unplug the cable, your Samsung phone plays a short charging chime. That sound gets annoying fast if you charge overnight, top up during meetings, or use a wireless charger that triggers it repeatedly. The toggle for this sound is easy to miss because it sits inside a separate system sound menu, not the regular notification settings.

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Apps & Installation2

Manage Full Screen App Display

When an app stretches oddly across the screen or crops content at the top and bottom, Samsung's full screen scaling is usually the reason. You cannot switch off full screen display system-wide, since it is tied to the display aspect ratio itself. What you can do is tell individual apps to render in the older, non-stretched format instead. This mainly affects apps that were never updated for taller Samsung displays and end up with distorted buttons or misplaced UI elements.

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Other2

Turn Data Usage Limit On or Off

Once your Samsung phone hits its set data limit, mobile data shuts off completely until the new billing cycle starts, even for calls or messages that need a data connection to send. Getting the billing cycle date or limit value wrong means losing mobile data days before your plan actually resets. The switch sits inside the Data usage settings and is easy to overlook once it is turned on.

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Storage & Backup2

Clear RAM on Samsung Phones

When too many background apps stay open, they occupy RAM and your Samsung phone starts lagging, freezing briefly, or reloading apps you just switched away from. One UI tries to manage memory automatically, but its automatic cleanup does not always catch every idle app in time. A manual memory clean-up gives you direct control over which background processes get closed right now.

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Display & Home Screen2

Set Default Home Screen Panel

Tapping the Home button always jumps to Samsung Daily instead of your main app grid? Samsung marks the second home screen panel, the one running Samsung Daily, as the default landing page. You can pick any existing panel on your home screen and make that one open instead.

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Display & Home Screen2

Change Theme (Display & Home Screen)

If your icons still look the same after downloading a new theme from the Galaxy Store, chances are the theme was never actually applied. Themes on Samsung phones control icons, wallpaper, and sometimes the style of stock apps, but they only take effect once you select and confirm them inside the Themes app. Simply installing a theme is not enough to change the look of your home screen.

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Notifications & Focus2

Enable or Disable App Icon Notification Badges

Little red dots or numbers keep piling up on app icons even after you have already checked the app. This comes from the App icon badges function baked into the home screen settings, and it applies to every app at once rather than one by one. If the count feels distracting or just wrong, it is worth knowing exactly which switch controls it.

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Accounts & Cloud2

Turn Auto Sync On or Off for Accounts

If your contacts, calendar entries or photos suddenly stop updating on your Samsung phone, automatic sync for that account is probably switched off. Auto sync data is the background function that keeps your Google, Samsung or other accounts current without you opening each app. Turning it off saves battery and mobile data, but new changes will only appear once you manually refresh or open the affected app.

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Network & Connectivity2

Manage App Location Permissions

If a delivery tracker or maps app suddenly can't find your position, you likely denied its location request the first time it asked, maybe by accident. On Samsung phones that first choice isn't final - each app's access can be reviewed and changed later. Mixing up 'Allow' and 'Deny' at the initial prompt is one of the most common reasons apps stop showing your location.

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Notifications & Focus2

Delete an Alarm

When your Clock app fills up with old wake-up times, work alarms, and one-off reminders, finding the one you actually need gets tedious. A cluttered alarm list also makes it easier to accidentally leave an unwanted alarm active, which can go off at the worst moment. Clearing out unused alarms keeps your morning routine predictable.

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Calls & Messages2

Customize Quick Decline Messages

When you reject a call with a swipe on your Samsung phone, a preset text like 'Please text me' or 'I will call you back' goes out automatically. If that message no longer fits the situation or you want a different wording, the default text stays unless you change it yourself. Many users only notice this after a caller mentions receiving a message they never wrote.

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Photo, Video & Media

Change Video Resolution

If your videos look pixelated or your storage fills up too fast, the camera might be set to the wrong resolution. Not every Samsung model offers the same options: some stop at FullHD, while others let you record in UltraHD. Picking the right setting depends on what you plan to do with the footage.

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Other2

Change the Edge Panel Handle Style

On Samsung phones, the Edge panel opens through a small black bar sitting at the screen edge, and that handle is not always easy to see or grab depending on your wallpaper. Some people find it too dark, too large, or just distracting when watching videos or playing games. The handle color, size, and transparency are separate settings from the panel content itself, so changing your wallpaper or theme will not fix how it looks.

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Apps & Installation

Allow or Block Apps for Edge Lighting

Edge Lighting only reacts to the Messages app by default, so notifications from other apps never trigger the curved glow. If a supported app is missing from the list, it stays invisible on the edge screen even with its own alerts turned on. You can pick exactly which apps light up the edge or switch on a setting that covers all of them at once.

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Photo, Video & Media2

Turn On/Off Mono Audio

If you share headphones or only wear one earbud, stereo playback leaves you missing half the sound. Samsung phones split calls, music, and video audio across left and right channels by default, so a single ear only catches part of the mix. Mono audio merges both channels into one so nothing gets left out.

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Other2

Change Device Name

If your Samsung phone shows up under an old or generic name when you connect via Bluetooth, Wi-Fi Direct, or NFC, other people nearby see that name too. This happens because the device name is set once during setup and rarely gets updated afterward.

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Network & Connectivity2

Change Preferred Network Mode

If your Samsung phone keeps dropping to a slower connection or won't pick up 4G or 5G even with full signal bars, the Network mode setting might be locked to an older standard. This option decides whether the device connects using 2G, 3G, 4G, or 5G, and a wrong choice here cuts off faster networks completely. On dual-SIM models each SIM slot has its own separate setting.

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Calls & Messages2

Mark a Contact as Favorite

If a contact you call or text often keeps sliding down your list, Favorites pins them to the top - but only once the flag is actually switched on for that person. On Samsung phones this same flag also controls the pinned row in the Phone app, so the two lists never match up on their own.

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Photo, Video & Media2

Floating Shutter Button: Turn On or Off

Selfies get tricky when the on-screen shutter icon sits out of thumb reach on a big display. Samsung's Camera app has a separate floating shutter release that you can drag anywhere on the screen, but it stays hidden unless you switch it on in the shooting methods. Without it enabled, you're stuck reaching for the fixed shutter icon or the volume keys every time.

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Other2

Find on Page in Samsung Internet

Scrolling through a long article to find one keyword wastes time, especially on news sites or long product pages. Samsung Internet has a built-in Find on page feature that highlights every match on the current page so you do not have to read the whole thing. Many users never notice this option because it sits inside the browser menu instead of the address bar.

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Other2

Turn Auto Optimization On or Off

If your Samsung phone closes background apps and clears memory every night without warning, the daily 'Auto optimization' routine is likely running while the screen is off. Some people want it active to keep the device fast, others notice messaging apps or trackers losing connection right after the nightly cleanup. Whether to keep it enabled or turn it off depends on how you rely on background apps.

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Display & Home Screen2

Turn On/Off Dark Mode

If your screen stays glaring white at night or your AMOLED display drains the battery faster than expected, Dark Mode is probably switched off. Samsung lets you enable it manually or have it follow a daily schedule automatically. Knowing exactly where this toggle sits in Display settings saves you from hunting through menus every evening.

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Network & Connectivity2

Turn Mobile Data On or Off

When mobile internet stops working outside WiFi range, or you want to cut data usage while traveling, the culprit is often the Mobile data toggle itself rather than a network issue. On dual SIM Samsung phones, only the SIM set as your default data line reacts to this switch, which confuses a lot of users. Data usage limits and background restrictions can also silently affect how this toggle behaves.

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