I need to change the tag search results layout. I did a change on serch.php and that works fine (I put 3 columms on search result to global search) and I need to put the same layout to tag search result. Thats more clear on pngs attached here. How could I change the layout to Tag search results?
I hope you are well today and thank you for your question.
The page that you have displayed in your shared screenshot is not a tag search results page but a tag archive page that you can change in the child theme using the theme archive.php template file.
Please find more information about the theme template files on the below page.