TXT is a file format that contains the text, organized in rows. Text files opposed binaries that contain data that is not intended for interpretation as a text (encoded sound or image). The text file can contain both formatted and unformatted text. Since the very simple text files, they are frequently used for storing data.
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.