Execution failed for task ':app:processDebugMainManifest'.
> Manifest merger failed : Apps targeting Android 12 and higher are required to specify an explicit value for `android:exported` when the corresponding component has an intent filter defined. See https://developer.android.com/guide/topics/manifest/activity-element#exported for details.

This following method can solve the problems above:

Add the following codes in app->manifests->AndroidManifest.xml:
android:exported="true"

Source:
java – Android Studio error: “Manifest merger failed: Apps targeting Android 12” – Stack Overflow