login, log in
Word list · L
Use login as a noun or adjective and log in as a verb. This guide prefers sign in for the action, while actual interface labels should be quoted accurately.
Noun: Keep your login private.
Adjective: Open the login page.
Verb: Log in to your account.
See also sign in; log off, log out.
Choose the wording that fits your meaning, audience, and voice.