How to change Apple ID to Apple Watch

Hello lornie257,

Thank you for posting in Apple Support Communities.

To change the passcode of your watch, follow these steps: 

1.    Open the Settings app on your Apple Watch.

2.    Tap Passcode, then tap Change Passcode and follow the onscreen prompts.

You can also open the Apple Watch app on your iPhone, tap My Watch, tap Passcode, then tap Change Passcode and follow the onscreen prompts.

Tip: To use a passcode longer than four digits, open the Settings app  on your Apple Watch, tap Passcode, then turn off Simple Passcode.

You can learn more about that here: Lock or unlock Apple Watch

Kindest regards.