How do I reset passcode on ipad

That would depend upon whether you know the current Passcode and can access the iPad - or not.

If you can access the iPad (which is not clear from your question), then you can change the Passcode from:

Settings > Touch ID & Passcode > Change Passcode

If you can’t access the iPad because you have forgotten your passcode, then you need to follow this Support article:

https://support.apple.com/en-us/HT204306

I hope this is helpful in resolving your query.