How to get ad_unit_id for Rewarded Ads from Admob?
You should use the following identifiers for testing (if you want to click on ads in your application) so that you are not banned:
For test Admob banner in you app you need use "banner_ad_unit_id":
For test Rewarded Ads in you app you need use "rewarded_ad_unit_id":
App Id for testing "admob_app_id":
After testing, and before publishing the application, enter your real IDs.
This guide assumes that your application is already registered with admob, if not: How to get banner_ad_unit_id from AdMob (Android App)