Unlock a password protected Apple Watch 6 series

Return it to Amazon;

The person that you bought/got this watch from needs to follow all the steps on this page;

Remove the Activation Lock so that the buyer can use it.

If they can't or won't then get your money back or recycle the watch and mark it down as a bad experience.

Neither the users on this forum or Apple can help you,only the original owner can help you.

I believe this is what you are looking for but keep in mind that if this is locked from the previous owner and they have find my watch enabled you will most likely need them to remove it from their Apple ID to use it. Apple does this to prevent theft

How to reset your Apple Watch if you forgot your passcode

1. Put your watch on its charger and keep it there until you complete these steps.
2. Press and hold the side button until you see Power Off.
3. Press and hold the Digital Crown until you see Erase all content and settings.
4. Tap Reset, then tap Reset again to confirm.
5. Wait for the process to finish, then set up your Apple Watch again. When asked, restore from a backup.