What is a PDF file and what are its uses?

PDF stands for "Portable Document Format", as such it is a file format that allows the user to view it over almost any available operating system. It contains not only the raw data (text, images), but also information on page size, formatting, margins amongst others. A file will be seen in exactly the same way wherever it is opened.

What it is

PDF format was developed by the Adobe Company in 1993. The idea was quite simple: To produce a document that would look like the final printed version. At that time, text processors still showed some differences between screen and printout. WYSIWYG
In this case, Adobe applied the WYSIWYG (What You See Is What You Get) concept, and PDF files were a visual printout of what would be processed by the printer. In fact, the process of PDF creation was to "Print" it to a special printer, the PDF "motor".

Main uses

The clear advantage of having a document that could be viewed on any platform (in modern times, this includes PDAs, mobile phones, tablets) gave the PDF format a winning standard. Of course, this specific use forced the addition of some features: - Write-protection: Documents had to be created and / or edited with a special software from Adobe, named Acrobat. - Electronic certificate and signature: To make sure that a file truly came from the named author(s). - Copy or print protection: Some PDF files can only be used as online reference, and they cannot be printed (or their contents cannot be copied to the clipboard). One special option allows for low-resolution printing. - Watermarking: It is similar to a signature. It is used for drafts, secret protection or partial demonstration files. (also for company branding) - Form processing: The included text can now be interactive with the user who may append or comment on information. This is quite useful for official documents, for example, that can be filled in without any special software.

How to view / create / edit PDF files

Adobe opened the PDF format so that there are multiple free viewers on the market. You can still download and install Acrobat Reader, the companion application to Adobe Acrobat (they are different applications). However, if you just don't want to view a PDF, and you also want to create a PDF file, you will need to choose between the existing PDF creators. Nitro PDF
You can find, for example, "Nitro PDF" (from Nitropdf.com) to create files from Word or Excel documents. An extract can be produced out of a PDF file, by re-printing the selected pages. If a combination of several PDF files is needed, applications as PDFTK Builder will do the job together with watermarking and write-protection amongst others.