An earnings call is like when you show your parents your report card from school and they ask you how you did in each subject. A company has an earnings call when they want to tell their investors and the public how much money they made or lost in a certain period of time, like a whole year or just one quarter.
During the earnings call, the company's CEO or other important people talk about things like how many products they sold, how much money they spent on making those products, and how much money they made from selling them. This helps the investors understand how well the company is doing and if they should keep investing their money in it.
Sometimes during the earnings call, people can also ask the important people of the company questions about anything they didn't understand or are curious about. After all, the better the understanding of the company's success and future plans, the better the investors can decide what to do with their money.