Okay kiddo, have you heard of phone numbers? Just like we have phone numbers to call someone, there are also numbers that are assigned to every device which connects to the internet. For example, your computer or phone also has an assigned number to make sure it can access the internet.
The group of smart people who manage and regulate these numbers is called the Internet Assigned Numbers Authority, or IANA for short. They make sure that every device connected to the internet has a unique identifying number so that it can communicate with other devices and access websites.
Think of IANA as the grown-up who makes sure everything is organised and fair on the playground. Just like how they make sure that each child has a turn on the swing or the see-saw, IANA makes sure every device gets assigned a unique number so that they can use the internet.
Overall, IANA is responsible for keeping track of all the numbers used on the internet so that it can continue to run smoothly and everyone can have fair access to it.