Samlpe letters request for evidence mother daugther relationship for USCIS

I do not understand your question. Are you asking about filing an Affidavit of Support (Form I-864) in connection with a pending Adjustment of Status Petition (Form I-485)? Or, are you asking seeking to prove an existing mother-daughter relationship in support of a Petition for Alien Relative (Form I-130)? If you are seeking to establish a mother-daughter relationship in connection with an I-130 Petition and do not have a birth certificate, you will need to file an affidavit, in which you swear to the facts which establish a mother-daughter relationship. You should write down the facts that establish the mother -daughter relationship. Discuss how she was raised, where you have lived, the times that she was taken care of by you, and any financial support that was provided to her. Tax returns that establish that she was a dependent will also help. Presence at confirmation, baptism, christening, or bat mizvah will also help. Any notary can witness it. Some banks and credit unions offer free notary services to its members. I hope this helps and may God less you.