Hello @pathan
Thank you for your question and welcome to our community!
We had questions similar to yours here on the platform recently. Please check out the information provided here:
https://***.wefugees.de/k/questions/2357
https://***.wefugees.de/k/questions/2279
In short: Yes, you are probably allowed to marry your fiancé if you can provide the required documents. Check out the answers linked above and get in contact with your local registry office to find out more about the details.
Feel free to ask further questions in case anything remained unclear.
Best regards,
Thorgen