You can import CSV files (comma separated values) to Cardfile.it. These files can be easily exported from Microsoft Excel, Google Sheets and many other programs.
Cardfile.it expects your data to be in following format. First row representing header with column names. Each following row representing a single record. Example:
Name, Year of birth, Instruments
Ian Anderson, 1947, Vocals Flute
John Cale, 1942, Vocals Keyboards Viola