The purpose of letters of acknowledgment is to provide proof that you have received specific documents or a specific type of request. If you are served on behalf of another person and you are authorized to receive process, you must indicate under your signature your authority.Begin with a professional letterhead or logo. Edit, sign, and share acknowledgment receipt online. No need to install software, just go to DocHub, and sign up instantly and for free. Edit, sign, and share acknowledging payment online. If further action from the recipient is necessary, include the next steps in the acknowledging receipt. Can't read the letters? Print the Certificate from the link on the receipt page or from the link on the purchased confirmation email. USCIS confirmed on social media that it was experiencing delays in issuing receipt notices for petitions filed at lockbox facilities.