I am in the process of filing the gc for my parents it seems form i 130 needs marriage certificate and i 485 needs birth certificate.

Secondary evidence of birth certificate for i 485.

Secondary evidence may include but is not limited to.
Proper complete birth records must be submitted.
But i produced secondary evidence as affidavits from 2 person along with non registration certificate from local government body municipality.

Birth certificate a copy of the applicants foreign birth certificate or sufficient secondary evidence of birth must be submitted to establish the applicants country of citizenship for visa chargeability identity and existence of derivative relationships.
In my parents case they neither have any birth certificate issued nor have a copy of marriage certificate.
It may include but is not limited to.

For some this is simply a birth certificate.
If you do not include it that will hold up the processing of your i 485 the issuance of the work permittravel document and ultimately the green card.
Delayed birth certificates are also not considered as conclusive evidence of birth.

Hospital birth records which have the names of the child and both parents.
If available you can also include a doctors or midwifes certificate as long as it has the names of the child and both parents.
The absence of an official record may be proven by a certified written statement by the official ordinarily having custody of such records or by an appointed deputy that after diligent search no record of the event is found to exist.

Medical records which have the names of the child and both parents.
Your evidence should corroborate the information on the birth certificate if you have one.
Submit as much evidence as possible.

The i 485 must be accompanied by supporting birth records.
There are a variety of documents you may use as evidence of the birth.
Examples include birth or baptismal certificates or other notable religious documents.

Birth certificates may pose a variety of problems.
She doesnt have birth certificate as that time it was not mandatory to register it.
Youll need to produce secondary evidence of the birth.

The applicant may also need a certificate of non availability.
See our article on evidence of birth for adjustment of status for a detailed explanation in the absence of any secondary evidence such as church school hospital or medical records two affidavits of birth may be submitted with form i 485.
I received a rfe as below.