Automatically use VoiceOver in the login window
Set a system preference to automatically use VoiceOver in the macOS login window.
Choose Apple menu > System Preferences, click Users & Groups, then click Login Options.
If Users & Groups preferences are locked, click the lock icon
in the lower-left corner of the window, then enter an administrator password to unlock them.Click Login Options, then select “Use VoiceOver in the login window.”
You can also turn this feature on or off in the VoiceOver pane of Accessibility preferences.
To turn on VoiceOver in the login window yourself, press Command-F5. If your Mac has a Touch Bar, you can press and hold the Command key and quickly press Touch ID three times.