How to add code to head section of the pages?

Hello all,

I have never worked with Drupal before so please if any responses could keep that in mind.

We are looking to make a mobile friendly version of our website, and need to add some code to the head section of the pages.

The problem we are having is we can't find where the pages are kept on the server? We simply need to know how to access and edit the head section of the pages, ideally via FTP/cpanel?

Any responses would be gratefully received.



I didn't find the right solution from the internet.

video animation