Okay, let's pretend you have a friend who always checks your homework to make sure you did a good job. This friend is like an auditor of your work. They look at your answers and make sure they are correct and that you did things the right way.
Now, imagine a big company like McDonald's. They have lots of money and lots of people who work for them. They need someone to check all their money and make sure they are doing things the right way. This is where auditors come in.
A company like McDonald's hires an auditor to look over all their money and see if everything is okay. The auditor looks at all the numbers and makes sure they add up correctly. They also check to make sure McDonald's is following all the rules and laws about money.
When the auditor is finished, they write a report about what they found. This report is like a letter to McDonald's telling them if they did a good job with their money or not. If McDonald's did everything the right way, the report will say so. But if they did something wrong, the report will say that too.
This report is also important for other people who might want to invest money in McDonald's. They want to know if McDonald's is doing things the right way before they put their money into the company. That's why the auditor's report is very important!