According to the United States Postal Service, there are three basic aspects of mailing an envelope. Before you get started, make sure that you have the return address, the delivery address and the proper amount of postage on hand.
Write the delivery address
The delivery address should be written parallel to the longest side of the envelope. The first line is the recipient line and should contain the name of the recipient. If the envelope is being mailed to a business, the second line should contain the business or company name. The next line should contain the address of the recipient, and the final line should contain the recipient's city, state and zip code.
Write the return address
The return address is written in the top-left corner of the envelope and should follow the same format as the delivery address. The return address tells the Postal Service where the mail should be returned in the event that it is undeliverable.
Affix the postage
The postage stamp should be attached in the top-right corner of the envelope. Postage price is based on a variety of factors; things such as size, shape, weight, distance and speed of delivery may all affect postage price. However, standard envelopes typically require only one postage stamp to be affixed to the envelope.
Mail the envelope
The final part of mailing an envelope is depositing it at a drop box or post office. Drop box and post office locations can be found on the official USPS website.