This article explains how to send a fax directly from the desktop version of Gmail and the mobile app.

After you sign up for an online service that supports faxing via email, the next step is to compose and send your fax. The Gmail address you plan to fax from should be the same email address registered with your fax provider. If it isn't, your sending attempt will likely be rejected.

Create a new email message in Gmail, either from within the app or through the browser interface, by clicking or tapping the Compose button.

Enter the recipient's fax number (including area code) in the To field, followed by the domain of your fax provider. For example, if you have an eFax account and are sending a fax to 1-212-555-5555, you would enter: [email protected]. This domain value (in this case, efaxsend.com) is specific to your individual fax service, so you should verify its exact syntax before completing this step.