You can use the send intent action (for example, the target is activity, the action isThere are apps that allow you to isolate activities inside other apps and to launch them instead of the full app (ActivityLauncher app or Nova f.e.) I would like to have them as an action.
android.intent.action.MAIN
, or android.intent.action.VIEW
, the package is the package name of your app and the class is where you should put the activity).