Log in to your Docusign account, by supplying your email address, but instead of supplying your password you now have the option to log in using your passkey;
Click on the 
button, and you will be prompted to enter the PIN code for your Fido2 key.
At the prompt "Security Key PIN", enter the PIN code, then click 
.
(in the case of a Fido key with a fingerprint reader you will need to swipe your finger on the key);
Next you will asked to touch the key;
Once the key has been touched you will be logged in to your Docusign account.