Take screenshots Settings > General > About (include "Model Name/Number and IMEI/SN) and upload its to https://imgur.com/, then copy link to "Screenshots (links)" text box.
The phone must be activated over 100 days !
Check IMEI here:
If result show ◯ or △ > can unlock, just submit IMEI.
If result show other is unpaid or blacklist, can't unlock !