Hi LERERA111,
I'm Dyari. Thanks for reaching out. I will be happy to assist you in this regard.
A security key is a hardware device, usually in the form of a little USB key that you can use instead of your username and password to sign in on the web.
Since it's used in addition to a fingerprint or PIN, even if someone has your security key, they won't be able to sign in without the PIN or fingerprint that you create.
https://support.microsoft.com/en-us/windows/win...
Security keys are usually available for purchase from retailers that sell computer accessories. However, there are some third-party tools that turn a USB drive to a security key but personally I do not recommend using them.
Please let me know if you need further assistance and keep me updated.