Interface arduino with geofencing

I couldn't find any code which uses Arduino Uno for geofencing, Can you please help me out with the code.
I'm going to use circular boundary for geofencing.
Is there any code for my requirement?
Basically, i'm using an arduino, a gps module, and hc12 on an object.
i need a code to connect all these and send a message to the server when object is moved outside geofence threshold.
Thank you.

I'm going to use circular boundary for geofencing.

So, the only relevant data is the center of the circle and the relationship between the distance between a point and the center of the circle and the radius of the circle.

What's even remotely hard about that?

i need a code to connect all these

Code does not connect hardware.

and send a message to the server when object is moved outside geofence threshold.

How is the message supposed to get to a server without WiFi or ethernet capability?

PaulS:
How is the message supposed to get to a server without WiFi or ethernet capability?

OP did mention HC12, I suppose that's for the communication.
But the problem is range of course, so take it too far away and it won't communicate any more. GSM may be a better solution.