Oppo
Enable App Lock auf Oppo
App lock in Coloros sits inside the privacy settings and stays disabled by default. Without it, every app on your Oppo phone opens directly from the app drawer or recent apps list, regardless of who is holding the device.
Turning it on adds a second authentication step - a dedicated privacy password, pattern or fingerprint - in front of each app you select. This is separate from your lock screen credential, so a stranger who unlocks the phone still hits a second wall before reading messages or opening banking apps.
Where to find App lock
The feature lives under: Tap on Settings ➔ Tap on Privacy ➔ Tap on App lock ➔ Turn On/Off the desired Apps. The first time you open this menu, Coloros asks you to set the privacy password that will later protect the selected apps.
App lock works well for apps holding personal data - messaging, gallery, banking, or notes. It does not replace the screen lock and does not encrypt app data; it only adds a prompt before the app interface loads. If you need to hide app content entirely rather than just delay access, check whether the app itself offers a built-in privacy mode.