1. Collect the names and addresses of all parties involved. This article provides a comprehensive sample of an affidavit letter, guiding readers through the essential components and format.Common for notices and to notify of a court hearing. How to write an Affidavit of Service? Simply fill in the required fields, sign, and submit. Use this free template to generate affidavits for legal proceedings, evidence documentation, and more. An affidavit of service, also sometimes called a proof of service affidavit, is a type of affidavit that relates to legal documents that are filed with a court.