Hi JohnDibble1,
Thanks for reaching out to Microsoft Community and posting your inquiry.
Windows Hello is a more personal and secure way to sign in to your Surface. The front-facing camera on the Surface devices recognizes your face and iris, which allows you to sign in to Windows 10 with just a look. If you have set up a 4-pin Password as a back up and with the Windows Hello face recognition, your device is more secured.
As for your goal to create a sub account, you can create a local user for your wife so she can log in using her own set up. To add her on the local user list, we suggest checking on the article, Create a local user account for more details and steps.
If this answers your question, we highly encourage you to inform our Community by clicking on Yes or marking my post as an answer. This will help other members who may have the same issue as you. Otherwise, don't hesitate to update us so we can further assist you.