Building a location-based grocery app: need advice on geolocation

Hello everyone,
I’m working on a grocery app where I need to implement location-based features. These are my current challenges

Receive the user’s exact location: I need to accurately capture the user’s location to show vendors around them.

Define the radius of the seller area: I want to define a radius around each vendor and give it a meaningful name (such as “Zone A” or “Downtown”). If the user is within that radius, their product feed will be filled with items from sellers in that specific area.

Track delivery: I also need to track the live location of the delivery person and display it on a map for real-time delivery updates.

Tools I use Spring Boot for the backend and React for the frontend.

Any advice, tutorials or similar experiences would be super helpful! Thank you in advance for your input.