You can use a Call Flow to route callers to an external number.
To create a call forwarding action, first create a Call Flow or edit an existing one you have attached to your virtual number. Follow the steps in this article to create a new flow.
Select the Forward to number component inside the list of available options
Connect it to the incoming call trigger directly, or use a phone menu to do more complex routings. In the example below, we will send the call to the number "+1 212 554 6666" when the caller presses the option "2" on the phone menu.
Save the flow, and your call forwarding will be ready.