Prathamesh Sonpatki has a useful post that shows how to make pull requests for GitHub and GitLab from Emacs using Magit. Sonpatki took some code from one of Artur Malabarba’s posts on Endless Parentheses and made the trivial changes necessary to get it to work with GitLab too.
Malabarba’s post is from 2015/2016 so you may not have seen it. Sonpatki’s post is, therefore, a welcome reminder. After completing and pushing a change to a new branch, you can use one of the code snippets to create a pull request from within Emacs. That’s useful because it allows you to stay within Emacs rather than having to switch out to your browser. If you’re an Emacs/Magit user and work with GitHub or GitLab you’ll find Sonpatki’s post useful.