How to Send a Text to Someone's Cell Phone From a Computer
You can send a text to any cell phone from your computer. All you need to know is the person’s phone number and cell phone provider. Each provider has a unique email suffix to ensure the message is correctly routed. Remember, most text messages can only be 120 to 160 characters.
Open your web email or email program.
Select “Compose” or “New” to start a new email.
In the “To” section type the recipient’s telephone number, including area code.
Type “@” and then the recipient’s cell phone provider's email suffix after the phone number. The suffixes for the major providers are AT&T: “txt.att.net,” Boost: “myboostmobile.com,” Sprint: “messaging.sprintpcs.com,” T-Mobile: “tmomail.net” and Verizon: “vtext.com.”
Give your mail a subject.
Type your message in the body of the email.