title: Editing files as a collaborator on GitHub
body: <p>I am trying to make changes to a GitHub repository for which I have been invited as a collaborator. I can create new files and modify them, but when I tried to do any changes to an existent file I saw this message saying "You must be on a branch to make or propose changes to this file".</p>
  
  <p><a href="https://i.stack.imgur.com/tDXEg.png" rel="noreferrer"><img src="https://i.stack.imgur.com/tDXEg.png" alt="See this screenshot"></a></p>
  
  <p>Then only after I push a commit through the terminal, I was able to modify this file on the GitHub pages. Is this an expected behavior? </p>
  
  <p>Thanks for your time,
  Cheers</p>