Has this Apple device been bypassed?

Why Check if an iPhone, iPad or Apple Watch Was Bypassed Before You Buy It?
When buying a used iPhone, it's important to verify whether the device has been bypassed to avoid future problems. Bypassed devices often have a hidden iCloud Activation Lock, which means they may be stolen, blocked or SIM-locked. Bypassing can also cause problems with software updates, notifications and network compatibility.

Check if your iPhone, iPad or Apple Watch was bypassed

To check whether your device was bypassed, follow these steps:

VERY IMPORTANT: DO THESE STEPS BEFORE YOU RUN THE CHECK, OTHERWISE THE REPORT WILL BE WRONG! (This check works only for iPhone, iPad and Apple Watch.)

1. Turn OFF Find My on your iPhone or other device.
Open Settings -> tap your name -> Find My -> tap Find My [Device], then turn it OFF -> enter your Apple ID password -> tap Turn Off.

2. Enter your IMEI or serial number below and click CHECK. (Double-check that the IMEI/SN is correct.)

Just enter the IMEI or serial number
Check
The check report will show one of these results:
1. Is my device bypassed? - YES - The device was bypassed and has a hidden Activation Lock.
2. Is my device bypassed? - NO - The device is not bypassed and you can restore it without any issues.

How i can find IMEI?
In settings
Go to Settings > General > About and look for your device's IMEI
Dial *#06# to get IMEI
Before trying anything else, you can try simply dialing *#06# on your iPhone (or any mobile phone), this should retrieve the IMEI number. Give it a moment and the IMEI will appear on the screen this little number dial trick actually works to retrieve the IMEI on other cell phones too, not just the iPhone.
On the back side of iPhone
The iPhone 5/5c/5s/6/6+ and the original iPhone have the IMEI number engraved on the back of the phone, near the bottom.
On the SIM tray
To find imei number, you need to remove Sim tray from the device, and then you can find IMEI/SN on it (not on all devices you can find IMEI/SN on the sim tray).