Updating your location is actually something quite easy: it's handled automatically by your phone.
All you have to do is to allow the geolocation both at the device and app level. To enable it within the app, simply make sure to visit Settings / Safety & Privacy / Use My Location. Once you're there, just toggle on Use My Location.
Note that's also where you'll find the ability to hide your city 💡
Your profile will always display your country to other users in the app, but you can decide to hide your city by toggling off Hide My City.