SXW is a text file format. From the very beginning, it was created for StarOffice Writer, that is, an application that processes texts from the Sun Microsystem StarOffice office suite. StarOffice was developed by Sun Microsystems. Then it was bought by Oracle. That's why Star Office has evolved into Apache Open Office, and is now a commercial Oracle product. At the same time, it is the same software product as the free program OpenOffice.org. The only difference is that the new Open Office provides technical support for packages. The Apache Software Foundation supports the Apache OpenOffice software package, and it provides a universal set of tools designed to work with vector drawings, spreadsheets, text documents, databases, etc. The .sxw file is an OpenOffice text document that is saved in XML-based Sun XML Writer (SXW) format. Currently, the SXW format and other OpenOffice formats that are outdated have skipped ahead of the family of standard OpenDocument Format (ODF) formats with .odt extensions without preserving compatibility between them. SXW files are opened by programs such as StarOffice Writer and OpenOffice.org Writer.
PDF is short for Portable Document Format, which can be translated from English as “Portable Document Format”. It was developed by Adobe Systems for use by US federal authorities as a tool for storing working documents. This is a universal cross-platform format, which is now standard for electronic documents. It serves to convert text files (including photographs or other images) into electronic documents without any loss. To read PDF files you need special programs - Adobe (Acrobat) Reader, PDF-Viewer and others.