The UK government wants to make sure that kids who are under 18 years old don't see things on the internet that they shouldn't see, like movies or websites with a lot of violence or bad language. So they're making a new system where websites have to make sure that people who want to see those things are over 18 years old.
To do that, websites will ask for something called "age verification," which means proving that someone is over 18 years old. They might ask for things like a credit card, a passport, or a driving license. Once someone shows that they're over 18, they'll be able to see the things on the website they want to see.
This is like when you might show your ID to prove you're old enough to see a movie or buy something in a shop. It keeps kids safe and makes sure they don't see things that are meant for adults.