Short answer: Yes thats a possible workflow.
Long answer:
Fork:
Is basically a copy of the openhab-docs repository where you can make your changes.
This is where your edit will be saved (at least temporary)
Pull Request:
This is the next step.
You edit the file (remember it is stored in your “fork”) and then you request a pull to the original files.
There a maintainer (in fact that will mostly be me for the docs) can check your changes and suggest improvements and additions.
At some point the Pull request will be accepted and get merged into the main docs.
One thing ahead:
When you will open your pull request you may see a red x saying your dco check has failed.
Don’T worry about that too mich. We can solve it and it is no veto against your pull request.
I have written down what happens (and how to solve it before) here.
But thats not mandatory to understand for a first pull request. 