Draft pull requests are available in public repositories with GitHub Free and GitHub Free for organizations, GitHub Pro, and legacy per-repository billing plans, and in public and private repositories with GitHub Team and GitHub Enterprise Cloud. For more information, see GitHub's products in the GitHub Help documentation.
To open or update a pull request in a public repository, you must have write access to the head or the source branch. For organization-owned repositories, you must be a member of the organization that owns the repository to open or update a pull request.
Pull requests let you tell others about changes you've pushed to a repository on GitHub. Once a pull request is sent, interested parties can review the set of changes, discuss potential modifications, and even push follow-up commits if necessary.