On Twitter, a notable person verifies who they are, and now they’re verified for all time (or until a billionaire buys the service and changes the verification policy). Whether verified or not, Twitter users must authenticate themselves with passwords and phone numbers.
Verification usually happens one time in any given system. Authentication is a repeated act to demonstrate that the person accessing something is, in fact, the person previously verified. Verification is: “Here’s proof that Mike Elgan is a specific person.” Authentication is: “The person attempting to gain access to a system is, in fact, specifically the previously verified Mike Elgan.”
Like Twitter, organizations of all types need both verification and authentication.