PHP include best practices question

Question

I have been learning syntax for PHP and practicing it. I come from a .NET background so masterpages always made things pretty easy for me when it came to headers and footer

Answer 1

I know this is very late, just wanted to add my "pennies worth" to this question.

My suggestion would be to create methods for this, e.g my root is: var/www/htdocs/ and the functions file is in includes/functions/template-parts.php.
My functions would look as such:

And used as such: