You’re probably trying to use APRSdroid. As you have discovered, that is a viewer that allows you to see APRS data that has been placed on the internet. A similar app for Apple exists, called APRS.fi, after the website where the data is available. It makes it very convenient to see where someone is if they’re carrying an APRS capable device that is sending information to an APRS digipeater on 144.390 MHz. The digipeaters and APRS capable radios are all ham radios. They can talk to each other directly or through digipeaters, but they use amateur radio. That should not be surprising; the founder Bob Bruninga, was a ham.
APRS does not exist on GMRS. It just doesn’t. There are no GMRS digipeaters and there’s no regulatory compliant path to place location data from a GMRS onto APRS.
But there some certified GMRS radios that pass location or text data between each other. Garmin was the first and BTech is another more recent one. This is why I keep asking if you really want APRS or if you just want some of the features of APRS. The features are possible. To actually fully implement APRS while remaining compliant with the regulations is not.
The regulations prohibit sending digital data to a repeater and the FCC currently interprets the regulations as prohibiting connecting GMRS radios to a network of any kind, so I don’t know how you’re going to put the data on a server.