If you want to do something like GitHub pages does with Jekyll, i.e. takes master and generates the website and then publishes the resultant files to the gh-pages branch, then you’ll need to set-up personal access tokens and use them in your GitHub action, for example

• Go to Personal access tokens
• Click on the “Generate new token” button
• In the Note field, give it a descriptive name so you know the purpose of the token
• If you’re wanting to interact with the repo (as we want to for this example) then check the repo checkbox to enable all repo options
• Click the “Generate token” button
• Copy the generated token for use in the next section

Once we have a token we’re going to use this in our repositories. So assuming you have a repo created, do the following to store the token

• Go to your repository and click the “Settings” tab
• Select the “Secrets<" option
• Click on the “New secret” button
• Give the secret a name, for example PUBLISH_TOKEN
• Paste the token from the previous section in the “Value” textbox
• Finally click the “Add secret” button

This now stores the token along with the name/key, which can then be used in our GitHub action .yml files, for example here’s a snippet of a GitHub action to publish a website that’s stored in master to the gh-pages branch.

- name: GitHub Pages Publish
  if: ${{ github.ref == 'refs/heads/master' }} 
    uses: peaceiris/actions-gh-pages@v3.6.1
    with:
      github_token: ${{ secrets.PUBLISH_TOKEN }}
      publish_branch: gh-pages
      publish_dir: ./public

In this example action, we check for changes on master, then use GitHub Actions for GitHub Pages to publish to the gh-pages branch from the ./public folder on master. Notice we use the secrets.PUBLISH_TOKEN which means GitHub actions will supply the token from our secrets setting using the name we gave for the secret.

Obviously this example doesn’t build/generate or otherwise do anything with the code on master, it simply takes what’s pushed to master/public and publishes that to the gh-pages branch. Ofcourse if we combine this action with previous build/generate steps as part of a build pipleline.