All radios have a phone button as do the steering wheels, whether Bluetooth is fitted or not.
Use the <> buttons on the right hand side of the steering wheel to scroll through the menus, if Bluetooth is fitted, it will show up in the MFD. If not, retro fitting is relatively straight forward using genuine parts. Most kits come with an adaptor harness that plugs between the radio and the bluetooth module. They just need a little bit of VCDS coding to make it all work.