Disable login with usename & password?

I apologize if this has already been discussed. I dilligently tried to search for it but couldn't find what I needed.

I have three pi's runing Octopi. Two of those have never required a login, the other I changed one of the config files so that I don't need to log in. I can't remember what I did or where I learned how to do it. Can someone refresh my memory on what to change? I'm setting up another with a 5" HDMI touch screen so that I can work Octopi while at the printer (PC is in another room). Thanks.

Do you mean the back end login of the system,
or the front end of OctoPrint?
(Info)

BTW: I never had problems with several OctoPrint installations and the logins. The Waterfox browser can handle several login informations without trouble. And it's more secure anyway.