Guide

1. Go to the repository where you want to add contributors.

2. Click on the 'Settings' tab near the top right of the repository page.

3. In the left sidebar, click on the 'Collaborators' button.

4. Github will ask you to confirm your Github password by entering your password and clicking the 'Confirm' button.

5. Click on the 'Add people' button.

6. Enter the GitHub username, full name, or email of the person you want to add.

7. Click 'Add' the user will receive an invitation to accept.

8. Select the level of access you want to grant.

9. The invitee will need to accept the invitation to become a collaborator.