Can someone please explain to me how anyone in the U.S. functions without a government issued I.D.? [View all]

I am not talking about a passport or a birth certificate. Asking anyone in the U.S. to have ready access at all times to either is nonsense. What I'm talking about is either a Driver's License or a State issued Identification Card. I ask this not in support of Trump's "SAVE" Act - A stupid name for a piece of legislation if ever there was one. The "SAVE" Act, if anything, is likely to create more confusion in our voting process than anything else. Hence, I am unequivocally against the "SAVE" Act. That said, I am curious how living as an adult in the U.S. without any government issued I.D. even works.