Documentation is like a big instruction manual for something. It's a bunch of information that people put together so that anyone who needs to know about that thing can learn how to use it or understand it.
In the field of work, it is important to write and keep track of documentation on what was done, how it was done, and why it was done. This way, people can look at the documentation in the future and understand what was done before. It's like taking notes in class so that you can review them later on.
Documentation can also help people in the future if they have a question or need help with something. They can find the documentation and read it to find the answer they need.
Overall, documentation is a way of keeping track of important information and making it easy for people to use or understand.