i forgot the passcode to my ipad mini

You erase it using your home computer with iTunes. Follow the directions in this link --> If you forgot the passcode on your iPad, or your iPad is disabled - Apple Support

Hello,

Unfortunately you must now fully restore your iPad to factory settings.

Please refer to the following Apple Support documents.

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

If you can't update or restore your iPhone, iPad, or iPod touch - Apple Support