When using Google AdMob, you first need to link your app to AdMob.
According to the AdMob help page, it may take up to a week after your app is published in the app store (e.g. App Store for iOS apps) before your app can be linked.
However, three weeks after publishing my iOS app, my app was still not found in AdMob and could not be linked to AdMob.
This problem has occurred many times in the past, and you can find many people's reports on the Internet.
- See Stack Overflow: App is not visible in appstore on Admob search
- One person reported that they could not find the app even after more than two months.
Ask in the Google forums for AdMob developers.
- Google Mobile Ads SDK Developers: https://groups.google.com/g/google-admob-ads-sdk
If you report a problem and ask for help on the above forum, Google's AdMob staff will help you solve the problem right away.
In my case, after reporting the problem in the above forum, I was able to get my app to show up in AdMob and link to it just 30 minutes later.