How to unlock my iPhone 6 without iTunes

You will need a PC with iTunes installed on the device or a Mac to reset the iPhone 6.

If you forgot your iPhone passcode - Apple Support

If you do not have a PC or Mac, you will need to borrow one, or take the iPhone 6 over to a friend's house.

You will need to know the Apple ID and Password that you used to originally set up the iPhone, since you will need it during the setup.

Once the iPhone has been reset and erased, you can use a backup of the iPhone to restore the data on the device.

Hello,

I think you forgot your passcode. Is that right?

If you forget your passcode you will not have access to your device. I recommend you to read this article and follow the steps given there. If you forgot your iPhone passcode - Apple Support

If you are unsuccessful, please contact Apple Support or visit an Apple Store or Apple Authorized Dealer.

Good luck!

Is not possible.

(< iOS 15.2) See this Apple article: If you forgot your iPhone passcode

If you forgot your iPhone passcode - Apple Support