PR, in the world of programming, stand for pull request. Although I absolutely despise acronyms, this one is widely spread, and it's good to get used to seeing "PR" in place of "Pull Request."
After you are done polishing your branch, it's time to get your code submitted into the official main branch. If you have recently pushed to your own fork, you may notice that GitHub asks you if you would like to make a pull request!
If you do not see this button, you can make a new pull request by clicking Pull requests >> New pull request.
Note that you can do this on your fork or on the official repository, just be sure to select the appropriate branches for your pull request!
You will be asked to provide a description. Please avoid using the default commit message / title. Put some love and care into your title. Your description doesn't have to be long, especially if you are resolving a ticket, but be sure to link to the appropriate tickets and provide any additional details or screenshots as appropriate.
Once you have given your code a final pass-through and are satisfied that your description and title are clear, click "Create pull request". If you know who should review your pull request, it is a good idea to click "reviewers" and select them from the list. Often, reviewers will connect this tag with a notification on their phone, so if you are uncertain who should review your pull request, leave it! The appropriate party will likely pick up the review on their own.
Of course, if it has been a few days and you feel your pull request has gone ignored, feel free to comment and mention a code maintainer!
Refrain from harassing core contributors. If they don't reply, they are either very busy or do not maintain the code anymore. Again, remember your code is reviewed by people, so be smart about how you treat others!