Is this a php page you are building, that displays the HTML and content within that PHP page? Or are you wanting to use a WordPress template to display content from within WordPress?

If its the second option check out https://developer.www.ads-software.com/themes/basics/template-hierarchy/ (in particular this diagram https://developer.www.ads-software.com/files/2014/10/wp-hierarchy.png) which shows you how to put together a php page to render a certain part of the theme.

If it is the first option, if you save the php file within your theme with a name such as my-file.php and you push it into your theme (say that is called my-theme) then your file should be accessible at https://my-domain.com/wp-content/my-theme/my-file.php.

I hope that makes sense.

If not, if you could provide a little bit more information I can try and advise further.

To use git to push changes a website, you would need to do the following (after asking your host whether you can even run git on your hosting, and how to set it up):

– Initialise a git repository on your server, in the folder where your code is, probably your theme or child theme.
– Set up your local computer with appropriate authentication for connecting to the git repository (probably an SSH key).
– Clone the repository from the server.
– Make your changes/additions. Commit them to your local repository.
– Push your local repository back to the server.