Collaborators are used to grant access to a repository owned by a personal account. To grant access to a repository owned by an organization account, see this guide.
Tip: Collaborators always receive read/write permissions. To grant read-only or administrator permissions to a repository, the repository must be owned by an organization.
- Visit the repository's page
- Click the "Settings" button
- Click the "Collaborators" tab
- Enter part of the user's login or email
- Select the user from the dropdown
- Click "Add"
Tip: Before they can be added to a repository, the person must have a GitHub account. If they don't have one, they can sign up on the free plan. Users can always collaborate on private repositories, even on the free plan.