how to unlock iPhone that is disabled

See these instructions, keeping in mind that if you don't have a backup all data will be lost on that device (except those that you eventually synced to iCloud):

If your device is running iOS 15.2/iPadOS 15.2 or later, AND if you have created a backup to iCloud, you don't need a computer:--> How to reset your iPhone, iPad, or iPod touch when you forgot your passcode - Apple Support

Shouldn't be this case (iOS/iPadOS earlier than 15.2), you need a computer. If you don't have a computer, borrow one from your friends/relatives/neighbors or ask for help at an Apple Store or Authorized Service Provider, then read these suggestions.

Given that to remove the existing passcode you must connect your device via USB to a computer (a Windows PC running the latest iTunes version, or a Mac, which can run iTunes or Finder, depending on the macOS installed on it), pay attention to the specific gestures that you need to perform while connecting your device to the computer.

These are the instructions to re-gain access to your iPhone/iPad:

If it is an iPhone:--> If you forgot your iPhone passcode - Apple Support

If it is an iPad:--> If you forgot your iPad passcode - Apple Support

Also, take a look at this support video about the same matter (for both iPhone and iPad):

https://www.youtube.com/watch?v=7s8-zLG9ySQ

Regards

Giulio

Please check ⤵️

1.

If you see a message that says "Your account has been disabled in the App Store and iTunes", there is a problem with your payment method on your account, to resolve the problem you need help from Apple support,  click -> contact Apple Support for help.

2.

If your Apple ID is locked or disabled -> If your Apple ID is locked or disabled - Apple Support (CA)

-> Get a verification code and sign in with two-factor authentication

Get a verification code and sign in with two-factor authentication - Apple Support

If you have followed all the steps and instructions and if you still need help, get more help and assistant from Apple directly, see Contact Apple for support and service -> Contact Apple for support and service – Apple Support (UK)