You can link an issue to a pull request using a supported keyword in the pull request description.
When you merge a linked pull request into the default branch of a repository, its linked issue is automatically closed. For more information about the default branch, see "Setting the default branch."
You can link a pull request to an issue by using a supported keyword in the pull request's description.
The syntax for closing keywords depends on whether the issue is in the same repository as the pull request.
|Issue in the same repository||KEYWORD #ISSUE-NUMBER|
|Issue in a different repository||KEYWORD OWNER/REPOSITORY#ISSUE-NUMBER|
|Multiple issues||Use full syntax for each issue|
You can also use closing keywords in a commit message. The issue will be closed when you merge the commit into the default branch.