Go to Settings > General > About . Look for "Carrier Lock." It should say "No SIM restrictions" . If it shows a specific carrier, it is locked to that network. 2. Hardware & Physical Inspection If you want to buy a preowned iPhone - Apple Support
When buying a used iPhone, your priority is verifying that the device isn't stolen or "bricked" before moving on to hardware health. 1. Critical Software & Security Checks buying used iphone checklist
These are the absolute deal-breakers. If a phone fails any of these, . Go to Settings > General > About
Dial *#06# to get the IMEI number. Check this number on a reliable site like the Stolen Phone Checker (US) or Swappa to ensure it hasn't been reported lost or stolen. buying used iphone checklist