A hardware key can be used as a passkey if it supports the FIDO2/WebAuthn standard.

If you are creating a new account and setting up your first 2FA (two-factor authentication), follow the steps below:

1. When prompted with “Where to save your passkey,” select “USB Security Key.” 
2. Insert your security key
3. Create a pin
4. Touch the key to complete the setup

If you are setting up a new 2FA for an existing account, follow the steps below:

1. Open your your Security Settings page
2. Scroll down to the "Passkey" section, and click the "Add" button
3. The system will automatically show a QR code. Do not scan this with your mobile device. 
4. Insert the hardware security key in the device you're setting up the passkey in.
5. With the QR code showing, touch your hardware key
6. You may see a modal asking you to set a PIN code for the hardware key
7. Click "Next"
8. Touch your hardware key again