Xiaomi
Assign a Custom Ringtone to a Contact auf Xiaomi
By default, MIUI plays the same ringtone for every incoming call, no matter who is calling. Assigning a separate tone to a contact lets you identify a caller by sound alone, without unlocking the screen.
This setting lives directly in the contact details, not in the general sound settings. It only affects calls from that one contact and does not change your default ringtone for everyone else.
Where to set it
Open Tap on Contacts ➔ Choose a Contact ➔ Open the Menu ➔ Tap on Set ringtone ➔ Choose a Ringtone. You can pick from the ringtones already installed on your phone or select a custom audio file if you have one saved.
The new tone applies immediately after saving, so a test call is the fastest way to confirm it worked. If the contact still uses the default sound, double-check that you saved the change and that the correct contact entry was edited, especially if the person has duplicate contact cards.
This works independently of Do Not Disturb or Focus profiles. If a custom ringtone does not play during a Focus mode, check whether that mode is set to silence all calls regardless of contact settings.