CSV stands for ‘comma-separated values’. While the format has been around for decades it’s still a useful way to store tables of information as plain text. And CSVs are supported by spreadsheet-style apps like Microsoft Excel, LibreOffice Calc, OpenOffice Calc, Google Sheets, Lotus 1-2-3 and many more.
Most coding languages are able to open and read CSV files. This includes the Python language installed on a Raspberry Pi or on a PC running Windows, macOS or Linux.