CSV stands for Comma Separated Values. A CSV file is a text file where every line corresponds to a line of the table, and every comma correspond to a separation between two columns. Most of the time, when opening a CSV file with Excel, you will see something impossible to read because the file is not opened correctly.
The easiest way to correctly open a CSV file in Excel is by importing it as data. You can find how to import data from TXT/CSV files in this Microsoft help center article. In this article, navigate to “Import a text file by connecting to it” and select the Office version you are using. Follow the steps in the article to open the CSV file.