Green Card

[immihelp]

I am a US citizen and applying for my parents green card. They have obtained certificates of non availability of birth records. They are going to get affidavits from relatives for their birth. Does this need to be on a stamp paper or plain paper if fine? Also, do they have to be notarized? If yes, who can notarize their affidavits.
Thanks for any help

[immihelp]

Read https://www.immihelp.com/birth-certificate-for-us-immigration-and-visas/