Resetting an iPhone passcode requires erasing the device, which deletes all data and settings, including the passcode. You can then restore your data from a backup. Here's how to reset your iPhone passcode:

Tips：If your iPhone was once connected to a computer and trusted this computer, you can still back up your data before the device shows that iPhone is unavailable.

Method 1: Using iTunes (or Finder on macOS Catalina and later)

Connect your iPhone to your computer: Use the USB cable that came with your iPhone.

Open iTunes or Finder:

On macOS Catalina or later, open Finder.

On macOS Mojave or earlier, or on a Windows PC, open iTunes.

Enter Recovery Mode:

For iPhone 8 and later: Quickly press and release the Volume Up button, then the Volume Down button. Then, press and hold the Side button until the recovery mode screen appears.

For iPhone 7 and 7 Plus: Press and hold the Volume Down and Sleep/Wake (Side) buttons at the same time. Keep holding them until you see the recovery mode screen.

For iPhone 6s and earlier: Press and hold the Home and Sleep/Wake (Top or Side) buttons at the same time. Keep holding them until you see the recovery mode screen.

4. Restore your iPhone:

In iTunes or Finder, locate your device.

You'll see an option to Restore or Update. Choose Restore. This will download the latest iOS and erase your device.

5. Set up your iPhone: After the restore process completes, set up your iPhone as new or restore from a backup.

Restore your iPhone, iPad, or iPod to factory settings - Apple Support

Method 2: Using iCloud (Find My iPhone)

Go to iCloud.com: Open a browser and go to [iCloud.com/find].

Sign in: Log in with your Apple ID and password.

Select your iPhone: Click on All Devices at the top and select your iPhone.

Erase iPhone: Click Erase iPhone. This will erase your iPhone and its passcode.

Erase a device in Find My on iPhone - Apple Support

Method 3: Using the iPhone itself (iOS 15.2 and later)

Enter the wrong passcode: Continue entering the wrong passcode until the iPhone shows the Erase iPhone or Forgot passcode option.

Tap Erase iPhone: Follow the on-screen instructions to erase your iPhone.

Sign in with your Apple ID: You will need to enter your Apple ID and password to erase the device.

Set up your iPhone: After the erase process completes, set up your iPhone as new or restore from a backup.

How to reset forgotten iPhone passcode?

Important Notes:

Backup: Ensure you have a backup before you start this process, as it will erase all data on your iPhone.

Apple ID and Password: You'll need your Apple ID and password to disable Activation Lock if it's enabled.