In this video I'll describe to how to setup AdMob App-Ads.txt correctly in you play store listing.
1. copy the app-ads txt code from admob app
2. create a file name "app-ads txt" file
3. upload app-ads.txt in your own hosting
Free alternative :) if u dont have a hosting site.
Is to upload app-ads.txt on free hosting.
https://www.app-ads-txt.com
Here is the detailed article on AdMob ads.txt
https://www.theissb.com/android/