You have to use SSH keys. Create one for each computer and register them all to the repo that you need to access. Doing this allows you to remove access computer by computer.
Once you have the SSH keys configured in Github, you can read this article to setup the Personal Access Tokens.
https://docs.github.com/en/github/authenticating-to-github/keeping-your-account-and-data-secure/creating-a-personal-access-token
UPDATE It tells you how to change to the token in the documentation
Using a token on the command line
Once you have a token, you can enter it instead of your password when
performing Git operations over HTTPS.
For example, on the command line you would enter the following:
$ git clone https://github.com/username/repo.git <--- HTTPS, not SSH
Username: your_username
Password: your_token <-------- THE TOKEN, not your password
Personal access tokens can only be used for HTTPS Git operations. If
your repository uses an SSH remote URL, you will need to switch the
remote from SSH to HTTPS.
If you are not prompted for your username and password, your
credentials may be cached on your computer. You can update your
credentials in the Keychain to replace your old password with the
token.
Instead of manually entering your PAT for every HTTPS Git operation,
you can cache your PAT with a Git client. Git will temporarily store
your credentials in memory until an expiry interval has passed. You
can also store the token in a plain text file that Git can read before
every request. For more information, see "Caching your GitHub
credentials in Git."
Also found a good video walkthrough that may help clear up a few things.
https://www.youtube.com/watch?v=kHkQnuYzwoo
