m31 app locks where it is available

[Thirukannan]

.

[Vrang]

Try this out
S secure by Samsung
http://apps.samsung.com/appquery/appDetail.as?appId=com.samsung.android.app.sprotect

[Sidhabhi]

Download s secure from galaxy store

[Juniorcoder]

it is available in settings menu them click digital well being.There you can find app locks with timers

[Ehsank]

If you want to use app lock from Samsung then download "S secure " from galaxy store ,

http://apps.samsung.com/appquery/appDetail.as?appId=com.samsung.android.app.sprotect