When you edit a file in another user's repository, we'll automatically fork the repository and open a pull request for you.

  1. In another user's repository, browse to the folder that contains the file you want to edit. Click the name of the file you want to edit.
  2. Above the file content, click . At this point, GitHub forks the repository for you.
  3. Make any changes you need to the file. New content in file
  4. Above the new content, click Preview. File preview button

  5. Type a commit summary and, optionally, an extended description. Commit message

  6. Click Propose file change. Commit Changes button
  7. Type a title and description for your pull request. Pull Request description page
  8. Click Create pull request. Pull Request button

Further reading