I have a client who needs his website edited, he is no longer in contact with the original creator of the site, and it seems that the creator used WordPress to make the website. I've been able to access the page through cPanel but cannot locate the HTML files necessary to do things such as editing text. I have the ability to change images but the owner would like to remove some pages, etc.
There are also tons of PHP files for the WordPress extensions and such, but I know nothing about PHP.
Would I need access to the wp-admin account that designed the page in order to modify the text?
Wordpress stores page content in a database, which is subsequently loaded by a collection of php files. You cannot change the content or looks of a wordpress site by changing html files.
The easiest way to change content is to log in to the wordpress dashboard of the website. If you don't have the password, you can open up phpmyadmin via cpanel, browse to the wordpress database and find the *yourwebsiteinitials*_users table. In there you can choose one of the accounts that should be there and click edit, then edit the user_pass column, and simply type a new password in value and set function to md5. Then you can go to *yourwebaddress*/wp-login.php in your browser and login with the user you just edited and the new password.
Alternatively you can find posts in the _posts table and change content via phpmyadmin, but it's much easier to do this via the dashboard.