In classic Outlook, it's no longer possible to sign out of your account or be prompted for a password to sign in.
For other options and more info, see Sign out of email.
In new Outlook​​​​​​​, it's no longer possible to sign out of your account or be prompted for a password to sign in.
You can sign out of a personal account (Hotmail, outlook.com, msn.com, live.com). For details, see Sign out of email.