A read receipt notifies the sender of an email that the recipient opened the message, and records the time at which he saw it. This confirmation is often used in business matters to prove that email recipients have in fact received such important documents as contracts and legal papers. As of July 2011, the option to request a read receipt for email sent from Gmail is available only through the Google Apps business suite for business and government accounts.
Sign into your Gmail account.
Click the "Compose Mail" button. Enter the necessary information in the "To" and "Subject" fields.
Click the "Request Return Receipt" link below the "To" field, and then click the box that appears to the left of the words "Request Return Receipt."
Compose your email message, and click the "Send" button located on the bottom left side of the screen.