Download the Zoiper app for your device at the following link:

You can also search for Zoiper in the App Store on your device.

To provision your Zoiper app:

1. Open the Zoiper app on your device.

2. Hit the QR button.

On iOS, the button is in the top left with this symbol:

3. Your camera will open with instructions on the screen.

Point the device at the given QR code and it will automatically be captured.

Once the QR Code has been scanned, your Zoiper app will auto-provision to your extension.

The Zoiper application and your iPhone need a couple of settings tweaked to allow for inbound call notifications.
a. In the Zoiper application, under Inbound Call Settings, enable both Force Background and WiFi Keep Alive toggles
b. Now, go into your iOS settings, to Notifications and turn on Notifications for Zoiper.

Note: If you are not an admin, you will need to contact your administrator for the QR code or provision your Zoiper app manually.