I recently misplaced my iPhone, and while I had set up a PIN along with my fingerprint for unlocking, I'm quite worried that the PIN isn't very secure. Is there a way to remove that PIN and keep only the fingerprint option for unlocking? I'm looking for a solution that doesn't require having physical access to my lost phone.
3 Answers
The best move right now is to go to iCloud and mark your device as lost. Once you do that, it locks the device down and protects your data, so even if someone finds it, they won’t be able to access it without the passcode.
Unfortunately, you can’t remove or change the passcode without having the device. The fingerprint and Face ID work as secondary methods, but the passcode is always a primary requirement for unlocking. So you’ll need that passcode in place for security.
You can’t change the passcode remotely because it’s stored on the Secure Enclave chip within the phone. In my experience with Mobile Device Management, you can send commands to reset the passcode, but you can’t choose a new one remotely. If you didn’t have Find My enabled, your options are pretty limited.

Do you need to have Find My iPhone enabled for this? I tried logging into my Apple ID, but it says I have no devices.