Car built on or after week 22 in 2015.
You might not have App Connect in all cars built during or after wk22 in 2015 as it was an extra cost option on the mk7 Golf. If you weren’t the first owner, the original owner might not have specified it.
Also, from what I’ve read on some other forums, it seems that some of the early MIB II infotainment units aren’t App Connect compatible if it wasn’t a factory fit option specified by the first owner. If you check in the car settings via the infotainment screen, if it’s compatible there should be an App Connect icon and selecting the option should generate a message something along the lines of ‘App Connect can be activated by means of an activation key available from the dealer’.