iPhone 11 username change

I just launched Lockwise after syncing my phone to my MacBook (running Mojave). My first attempt to log in to an app was almost successful. Lockwise remembered the password used on the Mac, but not the username. It put the password in both fields. After I finished with that app, I logged into Lockwise and found the entry. It will let me copy the username, but not let me edit it. Do I need to do that on the Mac version? How do I fix such errors?

(No, won’t update to next Mac OS as that would break Adobe CS6. :disappointed: )