how do unlock password/pin if you forgot the password /pin

It's a security measure. If you could bypass it it wouldn't be very useful.

You can hard reset/wipe your tablet - it will be completely erased, and unlocked, after that. If you post the kind of tablet it is, I can walk you though the hard reset.

if the google device manager is setup on the tablet to be able to ring and erase your device. You can lock and set pin then unlock with the pin and reset the pin.

If you try the wrong password/PIN enough times, it might ask you for your backup password, like for your Google account pw.

ok tell me how hard wipe and reset my password

It depends what phone you have. Do a search on line for "(your phone) wipe" or "factory reset".