Welcome to the Wefugees community and thank you for reaching out to us.
The marriage procedure in Germany was discussed on this platform a couple of times already. Please see, for instance, this thread for more information. If you follow the link and scroll down, you will find even more related questions.
Unfortunately, it will get really difficult to marry in Germany without a passport and the registry office will most likely ask for it.
As long as you are in the asylum procedure, you shouldn’t travel to another country (as to your partner in the Netherlands or Denmark, for instance, which has the reputation being easier/less complicated regarding the marriage procedure).
In order to get a binding information on the required documents, it is the best to contact your local registry office.
However, please don’t hesitate to get back to us with any further questions.
All the best,