I want to add and show google ads on Unity games. So showing ads will require app id declaration on a meta tag on apps manifest. I tried exporting the project opening on android studio and adding a meta tag on launcer folders manifest but I got error of manifest merger failed.
So How to add a meta tag on Unity exported files or right from the editor?

The problem: Editor builds apk but opening app gives ads ID error.
It builds apk with Unity 6.14f1 and Google ads V9.2 but opening on phone gives following error (even with blank project with ads libs in it only):

FATAL EXCEPTION: main (Ask AI...)
Process: test.app, PID: 2548
java.lang.RuntimeException: Unable to get provider com.google.android.gms.ads.MobileAdsInitProvider: java.lang.IllegalStateException:

******************************************************************************
* Invalid application ID. Follow instructions here:                          *
* https://googlemobileadssdk.page.link/admob-android-update-manifest         *
* to find your app ID.                                                       *
* Google Ad Manager publishers should follow instructions here:              *
* https://googlemobileadssdk.page.link/ad-manager-android-update-manifest.   *
******************************************************************************



at android.app.ActivityThread.installProvider(ActivityThread.java:8489)
at android.app.ActivityThread.installContentProviders(ActivityThread.java:7989)
at android.app.ActivityThread.handleBindApplication(ActivityThread.java:7675)
at android.app.ActivityThread.-$Nest$mhandleBindApplication(Unknown Source:0)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2478)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loopOnce(Looper.java:230)
at android.os.Looper.loop(Looper.java:319)
at android.app.ActivityThread.main(ActivityThread.java:8919)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:578)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1103)
Caused by: java.lang.IllegalStateException:

******************************************************************************
* Invalid application ID. Follow instructions here:                          *
* https://googlemobileadssdk.page.link/admob-android-update-manifest         *
* to find your app ID.                                                       *
* Google Ad Manager publishers should follow instructions here:              *
* https://googlemobileadssdk.page.link/ad-manager-android-update-manifest.   *
******************************************************************************
  


at com.google.android.gms.ads.internal.client.zzek.attachInfo(com.google.android.gms:play-services-ads-lite@@23.2.0:15)
at com.google.android.gms.ads.MobileAdsInitProvider.attachInfo(com.google.android.gms:play-services-ads-lite@@23.2.0:1)
at android.app.ActivityThread.installProvider(ActivityThread.java:8484)
... 11 more