Welcome.
Your car will have the Audio20 infotainment system with the optional (currently missing) Becker Map Pilot navigation processor.
You have several options.
1. Your car will have a bracket in the glove compartment, for the optional Becker Map Pilot navigation processor. You can buy online from Amazon or eBay a new unit or a second hand one. The latest maps can be bought online direct from Becker, for around 90 Euros. The advantage is that you'll get seamless integration of the satnav system with the Audio20 infotainment system and with the LCD display in the instrument cluster. The downside is that the Becker Map Pilot navigation processor is outdated in today's standards - it was released 13 years ago, and while the firmware and software updates over the years did help keep it 'fresh' to some extent, in its core it's not a modern unit. See also:
NEW CONDITION BECKER MAP PILOT WITH LATEST MAPS 2017/2018+FREE SPEED CAMERA!!! : Amazon.co.uk: Electronics & Photo
2. Upgrade the existing Audio20 infotainment system by replacing it with the higher end COMAND NTG4.5, that has built-in navigation with the maps on an internal HDD. The advantage is again seamless integration with the car, plus COMAND is a great system with better audio and better screen. The downside is that this retrofit requires professional installation and it is not cheap. If this is of interest, talk to
Comand.co.uk – Mercedes Retrofits Specialists – Unique Car Sound & Security
3. Fit an Android infotainment system with 10.25" screen, thus completely bypassing the car's original Audio20 unit (which will remain in place, but not be used). There are many Chinese manufacturers that make them, the brand Erisin has been recommended by some members here. The advantage is that you will have a system that can run any Android-based navigation software, plus it will have support for Apple CarPlay and Android Auto. This will allow you to use Waze, Apple Maps, or Google Maps. The main advantage is that the maps are always up-to-date, and you also get live traffic data. The downside is that the quality and reliability of the hardware isn't always great, and some dislike the look of the large screen 'stuck' on the dash. See also:
Erisin ES3640C 10.25" Android 11 Car Stereo GPS Sat Nav Radio for Mercedes Benz C-Class W204 NTG IPS CarPlay DAB+ 64GB IPS CarPlay Bluetooth
4. Install dedicated concealed hardware that will allow your existing Audio20 system to work with Apple CarPlay and Android Auto. See also:
AfterMarket CarPlay and Android Auto System (NTG3.5, NTG4.5, NTG5)
5. Get a mobile phone bracket and use your Waze (or similar software) directly from your smartphone.