Dear James Okafor,
Welcome back to the Wefugees Community and thank you for your question.
The marriage procedure in Germany is not dependent on a residence permit or a specific kind - even Duldung holders can marry. However, many people struggling with the variety of documents which are usually required. We published a blog on this topic which provides further information including a list of the documents you may have to submit.
One more question: The person holding a residence permit acc. to 28 is not already married (to a German), right?
I hope this helps and please don't hesitate to get back to us with any further questions.
All the best,
Meike