At the start , forgot 4 digit pass word,for ipadmini

There are several solutions to solve your problems. First you can try the default passcode 1234. But if you surely forgot 4 digit password, you have to restore the password. And below steps can help you.

1. Run the latest version of iTunes on your computer and then make sure that you do not connect your iPad with your computer.
2. For iPad with Face ID, you need to press and hold the top button or the volume button till you see the slider of power off shows up on the screen. Drag the slider from left to right to turn off your iPad. After that, plug your iPad into computer while holding the top button. You need to hold it until the recovery-mode screen appears.
For iPad with home button, you need to press and hold the slide or top button till you see the power off slider interface. Drag the slider from left to right to turn off your iPad. Afterwards, you need to insert your iPad into computer with proper USB cable while holding the home button. You need to hold the button until the recovery-mode screen displays.
3. In the interface of iTunes, you will see a dialogue for you to restore or update, you need to choose the option of "Restore" in the panel. Thus, iTunes will download program for your iPad. You need to wait for over 15 minutes until your iPad exit the recovery mode. Thus, you need to repeat steps 2-4.

4. Wait for the end of the procedure to set up and use your iPad without a passcode.
The process to remove iPad passcode via restoring iPad with iTunes is not so hard for you at all. You can give it a go to help you to pass through the passcode inquiry simply.

For more methods, check: Remove iPad Passcode through Restoring iPad with iTunes