Hi, I own a Ford Focus 2006 and I’m looking to buy a touchscreen navigation system to add to it. Does anyone have any suggestions on what systems are good to buy?

would be a great help, Thankyou very much

In honesty, I wouldn't buy a sat nav, just make sure you have a decent mobile phone and use Google Maps. It's superior to any fixed navigation system you can buy in nearly every way, and if linked to your car's audio can provide verbal instructions through the head unit. It also responds well to verbal commands, so you can ask it "Hey Google, Navigate Home", or "Hey Google, Volume 50%", or "Hey Google, Stop Navigation" etc. No need to press anything, it's automatic.

I have a touchscreen sat nav built into my car, and other than the fact the car's screen is bigger, the mobile solution is better, so that's what I use all the time 🙂

Google maps voice commands and directions work very well. But I’d go for a Tom Tom GPS with a decent size screen.  one of the reasons I went for the trim of focus I have was built in gps . I don’t like to be completely reliant on my phone for directions. 
google maps , Waze and Apple maps are all decent but obviously need phone and signal.