Hi think Tutorial is About how to create an ads.txt file in your cpanel or WordPress, this is not any problem or issue with Adsense this is a simple update which prevents third-party ads on your site.
Lets Start:
Method 1 for Cpanel USers
1. login into your cpanel then public_html

2. then create a new file and save with .txt

3. Copy this code and paste in ads.txt file
google.com, pub-0000000000000000, DIRECT, f08c47fec0942fa0
Important: Make sure you replace pub-0000000000000000
with your own publisher ID.

SAVE IT
Method 2. for WordPress
step 1: Login into our wp-admin dashboard
Step 2: click on plugins
step 3:then click on add plugins
step 4: then search for the file manager then install the file manager after an installed click on activate
Step 5: then add a new file and remain with ads.txt
then paste same code there
google.com, pub-0000000000000000, DIRECT, f08c47fec0942fa0
Important: Make sure you replace pub-0000000000000000
with your own publisher ID.
save it
NOTE: if ads are not showing after creating a file ads.txt make sure you did it properly. if everything is correct and ads are not showing on your website then wait for 48 hr to 3 weeks.