A pull request is a way of contributing to a Git project as a 3rd party. If you’ve found a bug or a way to improve something in an open-source project, you can use this to submit (commit) your changes to be reviewed by the moderators of that repo. The moderators have the ability to accept your changes and add them to their project, reject them, or alter and then accept them.
Git is a version control system designed for tracking file changes. It was created for allowing multiple people to work on the same project in a non-linear fashion. However, nowadays it is used for much more than that. Some use it as a simple tool to keep their data intact and backed up. Some use it to deploy their projects from their local environments to production since it’s faster and overall more reliable than FTP. Others use it to distribute code through sites like GitHub, and so on.
