`PR` is the abbreviation of `Pull Request`. Here's the definition of `PR` in the [official document](https://docs.github.com/en/github/collaborating-with-pull-requests/proposing-changes-to-your-work-with-pull-requests/about-pull-requests) of Github.
> Pull requests let you tell others about changes you've pushed to a branch in a repository on GitHub. Once a pull request is opened, you can discuss and review the potential changes with collaborators and add follow-up commits before your changes are merged into the base branch.
4. Push your changes to the forked repository and create a PR
+ Push the branch to your forked remote repository
```bash
git push origin branchname
```
+ Create a PR

+ Revise PR message template to describe your motivation and modifications made in this PR. You can also link the related issue to the PR manually in the PR message (For more information, checkout the [official guidance](https://docs.github.com/en/issues/tracking-your-work-with-issues/linking-a-pull-request-to-an-issue)).
5. Discuss and review your code
+ After creating a pull request, you can ask a specific person to review the changes you've proposed

+ Modify your codes according to reviewers' suggestions and then push your changes
6. Merge your branch to the master branch and delete the branch