Are you indoors at the time? Many phones use a database of Wi-Fi access point locations to determine your position when there is no available GPS signal. Additionally, the Google Maps are downloaded as needed.
You need an active mobile data or Wi-Fi connection to use Google Maps.
To find your location with Google Maps, you need to enable location sources. To learn how, see “Turning on location services” in this chapter.
The Google Maps application does not cover every country or city.