Welcome to Mailform! Mailform lets you send documents, letters and invoices via USPS Mail. Right from your computer. Simply, and securely. You enter the recipient address, enter your sender address (which is saved: if you've sent this document before, you can just confirm the address to use) and then send! You can choose to send in color or black and white, or to send it USPS Certified Mail (which provides a tracking number for important mail).