my daughter has disabled her ipad as she has forgot her passcode

If you forgot your pass code, you will need to erase your device

Follow the steps in this article:

If you forgot the passcode for your iPhone, iPad, or iPod touch, or your device is disabled - Apple Support

If you have a backup you can restore it from that

Restore your iPhone, iPad, or iPod touch from a backup - Apple Support

Hope this helps!

Follow the steps provided by the other poster, If you forgot the passcode for your iPhone, iPad, or iPod touch, or your device is disabled - Apple Support

My sons friend changed his password on his iPad and he doesn't know it and now the iPad is disabled from trying guessed passwords. Just need to reset that password.