How to add ads.txt or app-ads.txt files?

You can add ads.txt or app-ads.txt files in the Site Settings → SEO

To add these files, paste the lines that your ad network or a partner recommends into the field for the file you need to add and click the "Save" button.

Be sure to read the Google guide on working with these files.

Detailed guide: How to add ads.txt and app-ads.txt files