Assignees clarify who is working on specific issues and pull requests.
You can only create assignments for yourself, collaborators on personal projects, or members of your organization with read permissions on the repository. When creating assignments, you can add up to ten assignees to support your workflow.
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 assigned to someone.

- In the upper-right corner, click Assignee.
- To assign the items to a user, start typing their username, then click their name when it appears. You can select and add up to ten assignees to an issue or pull request.