It is possible to send an MMS message from a computer by using an email application. Sending an MMS message via email requires the sender to know the recipient's MMS gateway, which transforms the data in an email into a format that can be read by a mobile phone.
An MMS gateway looks similar to an email address, but it includes the recipient's mobile phone number. Each carrier has a different gateway, but every gateway uses a similar format. After obtaining the necessary gateway information, send an MMS message by typing a message in an email program and sending it to the appropriate MMS gateway. An MMS message to an AT&T cell phone with a telephone number of (555) 555-5555, for example, would be sent to firstname.lastname@example.org.