I don’t know my apple watch id password

If you forgot the Apple ID (iCloud) password, enter the Apple (iCloud) ID, and click Forgot Password. See if you can get a Rescue or Notification email option if necessary. Link to contact Apple Support at the end of the 2nd article.

Apple ID - Manage  -     

Apple ID – Forgot Password  *      

If you forgot the passcode for. the watch

Passcode - If you forgot your Apple Watch passcode.   *