What is a login system?
In general computer usage, logon is the procedure used to get access to an operating system or application, usually in a remote computer. Almost always a logon requires that the user have (1) a user ID and (2) a password.
What is the difference between login and log on?
In nontechnical web parlance, log on often means to visit (especially a website), and log in means to sign in with a username and password. For example, we could say you logged on to this website simply by visiting this page, but you won't be logging in because nothing on this site requires a username and password.
What is login screen?
A login screen is a web page or an entry page to a web/mobile application that requires user identification and authentication, regularly performed by entering a username and password combination.