CSV
From MoodleDocs
A CSV (Comma Separated Values) file contains tabular data (such as found in spreadsheets or databases) in a simple text format. Each value is separated from the next by a comma. Each line is a record and the commas separate the fields or columns. For example:
First name, Last name, Address, City, State Sally, Smith, 234 A Street, Town, Peace George, Smithe, 999 Last Lane, Hamlet, Denial Dim, Witt, By-the-Either, Wave, Outback
These files can be created, viewed and edited with software such as Microsoft Excel, Open Office Calc or, if done with care, any simple text editor.