how do i delete my passcode

Since you reference this from an Apple Watch support document, I'm guessing that you are asking about the passcode for your Apple Watch. If that is the case, then see page 9 of the User Guide. https://manuals.info.apple.com/MANUALS/1000/MA1708/en_US/apple_watch_user_guide. pdf

Just turn it off from the iPhone Apple Watch app. It's listed on the opening page under Passcode.