Creating your own ads.txt file allows you to control who can sell ads on your website, and it's a practice highly recommended by Google.
Get started by creating an ads.txt file following Google's ads.txt guide.
Once you create the file, open your website's integrations settings, and paste the file into the Google AdSense field:
Your ads.txt file should look like this, where
pub-0000000000000000 is your own publisher ID:
google.com, pub-0000000000000000, DIRECT, f08c47fec0942fa0.
Finally, save the changes and update your website.