CSV is an open file format, meaning any spreadsheet or database program can open and read the file. This video explains how to create (or save) an Excel file as a CSV file.
If you are using Facebook and want to create a custom audience using your existing customer database, you will need to save your file as CSV to import, or upload it into Facebook. To learn how to upload a CSV file into Facebook
How to format a csv file to upload to Facebook - [ Ссылка ]
