You email a PDF to a special email address @gmtfax.com that sends the PDF attachment as a fax to the number. The format of the email is always {country code}{fax number}@gmtfax.com. For example, if you wanted to send a fax to (855) 330-1239 in the USA. You would email your fax as a PDF to 18553301239@gmtfax.com. After a few seconds, you will receive a confirmation email that your fax is queued for delivery. Most faxes are delivered in less than 5 minutes.