If you want to write and send a letter to a friend or relative, there are a number of online services available. You can send a letter via email or print it out. The USPS website offers many options, including the ability to send letters to people who are not in your address book. You can even use a pen and paper to write a letter, if you want to write it in person. In either case, make sure to include the sender's address and a subject line. You will also need a copy of your letter, sufficient postage, and money to post it.
You can also choose to attach a PDF to your letter with Snailmailr. The interface is similar to that of writing a letter, and it provides templates for both types of documents. The message can be written in a standard typeface or in a handwritten style. You can also include a custom image instead of a text message. If you wish to create a unique postcard, you can upload an image to add to the postcard.
You can even use USPS mailboxes to mail a letter. There are USPS mailboxes throughout the US, including cities and suburbs. Visiting a post office will also let you see if a particular mailbox is located nearby. By paying postage and receiving a receipt, you can even track your letter. Once your letter is delivered, you can simply track the delivery with the tracking number that you've provided.