XLS format is used to refer to the documents of the program Microsoft Excel. This file is a spreadsheet. All document data distributed and stored in the cells. Each cell has a unique address, which is denoted by letters and Arabic numerals. The cell can contain fixed data, and data in the form of formulas, which bind more cells.
is a text format used for representing tabular data. Each file line is located on a separate line in the table. The values of the columns are separated by a delimiter, most often a comma. However, other symbols can be used as delimiters as well.