Hi, Pearl.
Sorry, I use the words ID and Drivers License interchangeably. We need to have our drivers license on us when driving. If you get pulled over or in an accident you need to show it plus proof of insurance. Plus it is also an ID for when buying alcohol, tobacco, cashing a check and such. I've long passed the age where I get 'carded' to show I am old enough to buy beer / wine at a store or bar.
added- An ID card is not necessarily a drivers license.
Do you not need to carry a driver license on you in the UK when you drive?
See
https://www.dhs.gov/real-id
My state, New York, is already issuing Real-ID driver's licenses. My license doesn't expire until 2020 and renewal is fairly expensive, so I don't want to renew early just to get a license with the Real-ID logo on it. Fortunately, TSA still accepts a US passport as proof of citizenship, so I can use it to board the domestic flight that I have to take to connect with an international flight to England. The international flight and entry into the UK require my passport anyway.
Renewal in 2020 to get a Real-ID license will be a bit of a hassle.
It requires your original Social Security card with your current name on it, which most younger people's parents got for them at birth in order to open a savings account for all the cash gifts. Goodness knows where the card is by now, so you have to contact the SSI office to get a new one. If your name has changed since issuance and you haven't gotten a new card, you need get one.
Two original proofs of current address, such as your current driver's license as long as your current address is printed on it and another one such as a utility bill or a bank statement. These must be originals received via Postal Mail, not picked up online as most are these days. The Department of Homeland Security is behind the times on that requirement.
US Passport or original birth certificate or several other options for non-US citizens in the country legally. How many people know where their birth certificate is? If not, and if, like the majority of Americans, you don't have a passport, and you don't know where your birth certificate is, you'll need to order a certified copy of your birth certificate from the relevant department in the state where your were born. For a price, of course.
Then you go to the nearest DMV office and stand in a long, slow-moving line, usually with a rude clerk at the counter when you finally get there. It's going to be a miserable couple of hours!