How to edit Not Found and Password pages?
You can customize the 404 Not Found page and the Password page using all elements you need from the Add elements button.
Click here to learn more about how you can edit pages.
When in the Website Builder editor, click on the Manage pages button.
To open the 404 Not Found page, click on the Not Found page in the Manage pages toolbar.
To open the Password page, click on the Enter password page in the Manage pages toolbar.