"Web indexing is like a big treasure hunt for the internet. When you use a search engine like Google, it's like having a map to find where all the treasure is hidden on the internet. But, before the search engine can tell you where to find something, it needs to know what's out there. That's where indexing comes in.
An indexing robot, or crawler, goes around to different websites and looks at everything there is to see. It looks at the pictures, the words, and the links to other places. Then, it takes all of that information and puts it in a big library (like a bookshelf) for the search engine to use later.
So, when you type something into the search bar of a search engine, like "puppies", the search engine knows to look in its library, or index, to find all the websites that have to do with puppies. It then shows you all the websites it found, so you can choose which one to click on and enjoy."