Must need; •Google Account •Google Voice Number •Google hangout Apps •Hangout Dialer 

openGoogle Hangouts App, open its start-up menu that’s available on the left side of the app. While iOS user has to users have to head to their Phone Number section of the settings, Android users can simply browse theirGoogle settings to access Google Voice section. Turn on the toggle for both Incoming Phone Calls option and Messages option. This gives you an access to making phone calls or sends text messages from the Google Hangouts App. Now all that’s left is to go back to the main settings page and click the Answer on Lock Screen toggle to enable the former functions of the app even in the lock screen mode. This enables you to access calling and messaging services with internet and eliminates the requirement of any cell service.