Viber is a free calling and messaging app, with features similar to that of WhatsApp. One more similarity it has with WhatsApp is that yes, it requires a phone number. You cannot use the app without it.
You have your own phone number/Sim card to be able to activate it and make your account.
To make an account on android, this is what you must do:
• Install Viber.
• Open Viber.
• Tap Continue.
• Select your country.
• Enter your phone number.
• Tap Continue.
• Tap YES.
• Enter the security code.
Now you are ready to use various features of Viber.
