how to find out which area my international galaxy s6 is from?

[Phil Simpson]

AP G920FxxU3COJ1
CP G920FXXU3COI9
CSC G920FOJP3COJ1
Model SM-G920F

 

[SpookDroid]

The CSC is what usually gives you the region, and in this case, it seems to match the VIR Region (UK).
YouFirmware - Galaxy S6 (SM-G920F) - (5.1.1) - United kingdom (VIR)

 

[Phil Simpson]

which 3 letters indicates the region in the CSC?

 

[SpookDroid]

I'm not sure it's just three letters, it's the whole code. At least I haven't been able to find a 'reasoning' behind it, I just look for the CSC number and see where it comes up in the list. In this case, it was UK.