The cell towers know where your phone is whenever it has signal. It's not as accurate as modern GPS, but 5G especially can locate you to within about a hundred meter radius. Precision varies wildly depending on conditions, distance, etc.

GPS is entirely passive (it is receive only), so leaving it on is harmless for your privacy on Apple devices. For Android... well, if you have an Android phone, you're not a privacy-conscious consumer by definition, so just leave it on for the convenience of not having to turn it on and off manually all the time!

WiFi, again, is not that big a deal with Apple because they rotate your unique MAC address to preserve your privacy. Android is a mixed bag, depends on the model of phone you purchased.