好像没有格式要求，我查到只要一个翻译证明人签字

Certification by Translator

I [typed name], certify that I am fluent (conversant) in the English and ________ languages, and that the above/attached document is an accurate translation of the document attached entitled ______________________________.

Signature_________________________________
Date Typed Name
Address

具体信息在http://www.uscis.gov/forms/forms-and-fees/general-tips-assembling-applications-mailing