How to find code file of a WordPress webpage?

I want to add something on a page of my WordPress site that is in localhost, but I can't find the file of that page in the htdocs folder from Xampp. I need the PHP file of that page to edit.

I searched in the "my site" folder in htdocs using some lines of code I can see when I inspect the source code of the page with SearchMyFiles.exe but nothing was found.

source https://stackoverflow.com/questions/75979587/how-to-find-code-file-of-a-wordpress-webpage