How do I bypass a locked iPhone?

If it was locked from too many attempts to unlock it, you will need to reset the iPhone and this will delete all data on the phone. Obviously there is no way to bypass it, as that would defeat the purpose of protecting your data in the first place.

If you forgot your iPhone passcode or your iPhone is disabled - Apple Support

If you do not know the Apple Account Password after resetting, the phone will remain Activation Locked until that can be entered or you submit the proper purchase receipts to prove the device is yours. In most cases that will have to be the original receipt from Apple or Authorized Apple seller as Apple does not get involved in third party sales.

https://al-support.apple.com/#/additional-support

If your phone is locked, you will either need your passcode, or use FaceID/TouchID to unlock it.

The fact you're asking, though, implies there is more to your question, but without more context there's no way to be more specific.

What specific issues are you having unlocking your phone? When was it last unlocked? what's changed since then?

Here are the various different iPhone things that can be unlocked:

• How to Unlock an iPad or iPhone? - Apple Community

and what to do about each.

Bypass in what way?