Nebraska Certified Mail Proof of Service is a service provided by the United States Postal Service (USPS) to help Nebraska residents provide proof of service of a legal document. It is a secure and reliable way to provide proof of service for any legal document that requires it. Nebraska Certified Mail Proof of Service comes in two forms: Certified Mail with Return Receipt and Certified Mail with Restricted Delivery. Certified Mail with Return Receipt provides proof of delivery with a signature from the recipient upon delivery. Certified Mail with Restricted Delivery allows the sender to restrict delivery of the document to only the intended recipient. Both services provide a tracking number, so the sender can track the progress of the legal document.