Add the AdSense Code to every page on your site
The code tells Google AdSense that the page belongs to your site. It needs to be on every page. To add it to every page copy the HTML code from the AdSense console to the clipboard, login to the Joomla! 4 Administrator, Choose 'System' --> 'Site Templates' and then choose 'Cassiopeia Details and Files'. Look for 'Index.php' in the list of files and click to edit it. Paste the code you placed on the clipboard in the HTML of your site, between the <head>
and </head>
tags.