GPS location not accurate

GPS by itself requires a clear view of the sky. Thus, it cannot work if you are indoors, or even in a location with heavy tree foliage. That's why the iPhone supplements GPS satellite signals with Wi-Fi, cell tower triangulation and Bluetooth. For the most accurate location results you need to have Wi-Fi and Bluetooth turned on. The phone can use Wi-Fi and Bluetooth signals for location even if you are not connected to any Wi-Fi network or Bluetooth devices.

Hi Saheel19!

Welcome to Apple Support Communities!

I see that you have some concern over GPS location in Maps, and I'd like to help out. This is a great article about how Location Services uses GPS and Bluetooth (where those are available) along with crowd-sourced Wi-Fi hotspot and cell tower locations to determine your device’s approximate location: Location Services & Privacy

What you can do to verify there isn't an issue with your iPhone, is to test in multiple locations, using Wi-Fi and cellular data.

Are all locations not accurate?

Does Wi-Fi give more accurate locations?

Keep in mind that your location is approximate, not exact.

More info can be found here: About privacy and Location Services in iOS 8 and later

Cheers!