Google Adsense Authorization for Digital Sellers, or ads.txt, Here is a simple ways wordpress and blogspot users can implement or Declare authorized sellers with ads.txt.
The Adsense support forum answer can be found here
On the above link, you will see something like this:
“Create your own ads.txt file for AdSense
Here’s how to create an ads.txt file to publicly declare that Google is authorized to sell your ad inventory:
1. Create a text (.txt) file.
2. Include the following line:
google.com, pub-0000000000000000, DIRECT, f08c47fec0942fa0
Important: Make sure you replace pub-0000000000000000 with your own publisher ID.
Host your ads.txt file at the root level of your domain. (for example, ).
Root levels are one level down from what’s listed in the public suffix list”
For wordpress plugin you can use Ads.txt manager, Ads.txt Admin, Simple ads.txt, etc.