how do i reset my passcode when find my device is offline and when its on iphone unavalable

I understand that your iPhone is in the state of “Unavailable”. You are therefore locked out of your iPhone. You will have to reset the passcode to your iPhone by following the instructions in this guide published by Apple 👉 If you see a iPhone, iPad, or Apple Vision Pro unavailable message or Security Lockout screen.  Note: All the data on your iPhone will be erased.

Hopefully, you have a backup created on 👉 iCloud and/or on a computer. If you do then, you can 👉 Restore your iPhone from the backup file once your passcode has been reset and the iPhone has been returned to factory settings by the procedure in the link above.

Axel F.

You cannot reset the passcode unless you have the phone in your possession.

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