Method 1:
Long press the app icon and click on the App Info
a. Click Force Stop to end the process of running the application.
b. Click Battery Usage to turn off Allow background activity and Allow auto launch, Allow this app to launch other apps.
Method 2:
realme UI 7.0 & 6.0: Settings > Accessibility & convenience > Process manager > Deep cleanup > End all
realme UI 5.0 & 4.0 & 3.0 & 2.0: Settings > Additional / System settings > Process manager > Click Deep cleanup
realme UI S & T & R & Go & U Edition: Not supported