You can own repositories individually, or you can share ownership of repositories with other people in an organization.
You can restrict who has access to a repository by choosing the repository's visibility. For more information, see "About repository visibility."
For user-owned repositories, you can give other people collaborator access so that they can collaborate on your project. If a repository is owned by an organization, you can give organization members access permissions to collaborate on your repository. For more information, see "Permission levels for a user account repository" and "Repository permission levels for an organization."
Each person and organization can own unlimited repositories and invite an unlimited number of collaborators to all repositories.
You can collaborate on your project with others using your repository's issues, pull requests, and project boards.