You can include an open source license in your repository to make it easier for other people to contribute.
If you include a detectable license in your repository, people who visit your repository will see it at the top of the repository page. To read the entire license file, click the license name.
Open source licenses enable others to freely use, change, and distribute the project in your repository. For more information on repository licenses, see "Licensing a repository."
Including an open source license in your repository
On GitHub, navigate to the main page of the repository.
Above the file list, click Create new file.
In the file name field, type LICENSE or LICENSE.txt (with all caps).
To the right of the file name, click Choose a license: None to choose your desired license. If you don't find the license you want, manually paste the full text.
At the bottom of the page, type a short, meaningful commit message that describes the change you made to the file.
Below the commit message fields, decide whether to add your commit to the current branch or to a new branch. If your current branch is
master, you should choose to create a new branch for your commit and then create a pull request.
Click Propose new file.