Ads.txt stands for Authorized Digital Sellers and is a method for publishers and distributors to declare who is authorized to sell their ad inventory. You can learn more about it here.
1. How to implement ads.txt for Google ads
Please jump directly to step two if you already have an ads.txt file.
The following steps describe only how to create an ads.txt file for Google ads. You can read more information and refer to Google's full guide here.
1.Create a text (.txt) file.
2. If you have an AdSense, DoubleClick for Publishers (DFP), or Ad Exchange account managed by yourself (not through a third party), include the following line: google.com, pub-0000000000000000, DIRECT, f08c47fec0942fa0
If you are not sure how to host your ads.txt file at the root level of your domain you can install the Ads.txt Manager plugin. It will help you create, manage, and automatically validate your ads.txt from within WordPress.
The validation baked into the plugin helps avoid malformed records, which can cause issues that can lead to a drop in ad revenue.
After installing and activating the Ads.txt Manager plugin:
Go to Settings (from your WordPress dashboard) > Ads.txt