how to submit additional evidence in writ of mandamaus

Please clarify whether you have engaged any lawyer to handle the case or not.

Hi. You can simply make an affidavit with the documents attached which you wish to rely on. You can file and submit this affidavit to the court with the leave of the court. If the documents are relevant for adjudication of the matter, then the court will accept your affidavit. You can submit that you wish to place certain facts on record through certain documents and seek liberty of court to file an affidavit in that behalf. 

Thanks Yousuf Sir