A CSV (comma-separated values) file is a simple text file where information is separated by commas. CSV files are most commonly used in spreadsheets and databases. For example, you might have a list of customer details, if you export them as a CSV. file, you'd get a file containing text like this: Name, Email, Phone Number, Address. Bob Smith, email@example.com, 123-456-7890, 123 Fake Street.