There was a tutorial that showed me how to do it when I set up the website via Wordpress. It was manual and I copied and pasted the keys per the tutorial. I am currently locked out of wordpress waiting on a password reset. I can access CPANEL but I can't find the instructions on how to generate the key.
Year ago (last time I looked) Wordpress had plugins for setting up Let's Encrypt certificates, I assume these still exists or it's built into either cpanel (such as How to Configure and Manage Let’s Encrypt in cPanel | cPanel Blog) or wordpress now. You shouldn't be having to do manual stuff, especially with cpanel.