When you make something on your computer, like a document or a picture or even something big like a video game, your computer needs a place to store all of the information that makes up that thing.
Sometimes, your computer will need to create what's called a "temporary file" to help it do that. A temporary file is like a scratch piece of paper - it's not the final thing you want, but it's helpful to have around while you're working.
For example, if you were creating a big report for school and your computer needed to crunch some numbers to make charts and graphs, it might create a temporary file to store those numbers in while it's working. Once it's done, the temporary file is deleted and the final report is saved as one document.
Temporary files can also be used to store information about things you're using on your computer, like web pages or photos. They're usually created automatically and you don't need to worry about them too much.
The important thing to remember is that temporary files are just like scratch paper - they're meant to be used and then thrown away. So if you ever see them on your computer, don't worry - your computer is just doing its job!