You can use a tool like to check if your file is a proper csv. Another option is to upload the file to Google drive and open it as a google spreadsheet and then download it as a csv (file -> download as -> csv. A third option is to open your original file in LibreOffice and save as csv (this has the added benefit of enabling you to change the encoding if you want). All of these options give you good csv files that adhere to the standard about which you can read more here:

If you export from Excel you should note that you need to make the file comma separated and not semi colon separated.