The *.xlsx or *.xls format is a file
format used for storing spreadsheets,
and it is primarily associated with
Microsoft Excel, a popular spreadsheet
program included in the Microsoft Office
suite. Xlsx is the default format used
for Excel worksheets since Excel 2007.
Xls is used for Excel4.0/5.0/95/97.
The .xlsx format features XML-Based,
open standard, Cell and Sheet
Formatting. Xls is binary format and
supports legacy version. Security
features are password protected.
PDF, which stands for Portable Document
Format, is a file format created by
Adobe Systems in the early 1990s. It is
a widely used and versatile file format
for documents, designed to present and
exchange documents reliably, regardless
of the software, hardware, or operating
systems used by both the creator and the
recipient. It features platform
independence, consistent formatting,
security, interactive elements,
compression, annotations and comments,
digital signatures, accessibility,
printability, archival format.
The web app can convert Microsoft Office
format to pdf online.