NEW USERS LIMITED OFFER: 3-day trial for one free phone number. Duo Phone Number, a private 2nd Phone number app, is a calling and texting app that allows you to make calls and send text messages globally. It is also a phone number app without a traditional registration process. It also provides multiple phone numbers as a sideline on your smartphone to let you call and text for personal use and work separately. Key features: *Get a phone number and make free phone calls and send free texts wi