If you forgot your passcode and your iPhone is disabled, you need to erase your iPhone and set it up again.
The only way to do this is to put your iPhone in recovery mode and connect it to a computer with iTunes or Finder. This will erase all your data and settings, including the passcode, and install the latest version of iOS or iPadOS on your iPhone. You can then restore your data and settings from a backup, if you have one, or set up your iPhone as a new device. To put your iPhone in recovery mode, you need to follow these steps:
* Make sure that your iPhone is not connected to your computer, then turn it off completely.
* Press and hold the correct button for your iPhone model while connecting it to your computer. For iPhone 8 and later, use the side button. For iPhone 7 and 7 Plus, use the volume down button. For
* iPhone 6s and earlier, use the home button.
* Keep holding the button until you see the recovery mode screen on your iPhone, then release the button.
The recovery mode screen shows a cable and a computer icon.
* On your computer, open iTunes or Finder and locate your iPhone. You should see a message that says there is a problem with your iPhone that requires it to be updated or restored.
* Choose Restore to erase your iPhone and install the latest software. This may take some time, so do not disconnect your iPhone until the process is complete.
* After your iPhone is restored, you can set it up again using the onscreen instructions. You can choose to restore from a backup or set up as a new device.
References: = If you forgot your iPhone passcode; Apple Device Support Exam Prep Guide, page 8.