On iOS
1. Tap on your profile picture > Phone.
3. A reminder is shown in Phone > Calls tab. Tapping on it will give the user the ability to enable incoming calls.
On Android
1. Tap on the hamburger button (three horizontal lines) on the upper left
2. Tap Settings > Phone.
4. A reminder is shown in Phone > Calls tab. Tapping on it will give the user the ability to enable incoming calls.