In repositories where you have write access, you can assign labels to issues and pull requests to help organize your projects.
Tip: You can also apply a label in the Labels drop-down menu within an issue or pull request.
On GitHub, navigate to the main page of the repository.
Under your repository name, click Issues or Pull requests.
Select the checkbox next to the items you want to apply a label to.
In the upper-right corner, click Label, then start typing the name of an existing label. Click the label's name to associate it with the selected items.