Resources » Working With PDFs (Basics) » What Is a PDF File, Anyway? (And How Do I Open It?)

What Are PDF Files, and How Do You Use Them?

The definition of a PDF is portable document format, but what does that mean, and how do you use PDF files? We’ll explain PDF basics, starting with a little history lesson and then showing you things you can do with the PDF document format.  

The portable document format, or PDF, is a digital file format that is meant for presenting and transferring information in an easy-to-share format, without losing the settings set by the original creator. In effect, the PDF that you receive is exactly what the sender intends you to see. The original file could have been created in Photoshop, Illustrator, Microsoft Word, Google, Canva, PowerPoint or any number of programs. The power of the PDF is in its versatility and compatibility. There are, literally, hundreds of applications that produce files in hundreds of formats. Not all of us have the software required to open and view hundreds of formats. PDF is like a common language that most people’s devices can work with. 

The PDF was first developed by Adobe co-founder John Warnock in 1991 as part of The Camelot Project. The goal of Camelot was “to communicate visual material between different computer applications and systems… There is no universal way to communicate and view this printer information electronically.” Basically, when you print a document, that physical copy has its formatting settings preserved and anyone who receives that physical document will see the same thing. Camelot sought to create a digital version of that very concept and, by 1992, Camelot did just that. 

The PDF was one of the results of The Camelot Project. If you’re transferring documents across the web, even today, you can be assured that anyone that views your PDF will see the same thing.  

How Do You Make a PDF?

PDFs are fairly easy to make on common document editors and web browsers. In fact, most programs where you view document content have an option to export as PDF.

When saving or downloading a document, you will likely see an option to “save as PDF” or “download as PDF.” Upon selecting this, the program may show you a preview of the resulting PDF. 

In Microsoft Excel, for example, when you export a sheet as a PDF, it will reformat the spreadsheet into something that better fits on individual pages. Be aware that you may need to change the formatting settings, depending on what your goal is with the resulting PDF. 

You can also easily make PDFs using any web browser. Simply go to the settings section, usually at the top right of your browser, and select Print. Then, in the destination section, instead of selecting a printer to print a physical document, choose Save to PDF. This will allow you to save a PDF copy of the webpage you currently have open in your browser. 

If you were sent a document in a file format different from PDF such as .DOC or .XLSX, you can use a PDF converter tool to turn that document into a PDF. offers a variety of PDF conversion tools that you can find in our convert PDF section. 

Benefits of PDFs

Why would you need to use a PDF? If you’re sending or otherwise transferring documents across the internet, it’s likely the person on the receiving end won’t use the same document editor that you do. But the PDF is viewable using any web browser and will maintain its formatting settings. Here are some of the benefits to using a PDF:

  • Convenience: PDFs do not have large file sizes and are easy to send, download, and read.
  • Secure: The PDF has security features such as locking the document with a password so that it’s read-only.
  • Graphically consistent: If your document has a lot of pictures or diagrams, the PDF will preserve the sizes and settings of the information so everything is exactly where you need it to be.
  • Cross-program: Whether you’re using a Windows, Mac, or Linux computer, mobile device, you can open and view a PDF on anything.

How Are PDF Files Used?

PDFs are most commonly used for transporting information that is meant to be viewed and not edited by the recipient. Here are some common uses for PDFs:

  • Resumes
  • Cover letters
  • Portfolios
  • E-books
  • Invitations
  • Pamphlets
  • Design documents
  • Contracts
  • Official reports
  • Articles
  • And more!

The possibilities are endless with PDFs. No matter what document you need to transport across the internet, the PDF will be the best option. 

How Do You Open a PDF?

Opening a PDF to view is very easy. You don’t need a fancy program to just view a PDF. 

To view a PDF, first make sure that you’ve downloaded it, then locate it in your File explorer (Windows) or Finder (Mac).

On a Windows PC, open a new browser window (Chrome, Firefox, etc.) and click the PDF and drag it to the web browser. You’ll see the PDF is now viewable in a new tab on the browser, as if it was its own website. However, you’ll notice in the address bar, instead of a web address, the location of the PDF file on your computer will be listed.

screenshot showing what a sample pdf looks like in pdf live's pdf editor

Mac devices have the program Preview built into their systems, which is a free PDF viewer and editor. On your Mac device, locate the PDF file and double click it. The Preview program should automatically open it. 

icon showing the apple preview app on a mac

If you’re on an Android Device or an iPhone, you only need to download the PDF and locate the file in your Downloads or My Files section. Then tap the PDF and it will open for you to view. 

What Else Can You Do With PDFs?

If you’ve opened a PDF on one of these devices, it’s likely you’ve noticed that you won’t easily be able to edit a PDF without an external program such as the aforementioned Mac Preview app. Oftentimes, the owner of the original PDF will “build” the document in an app such as Microsoft Word and then export or save a version as a PDF. This PDF version of the document is meant to be shared and viewed — not edited. 

However, if you need to edit a PDF, has a PDF Editor tool online that works with all devices. This tool allows you to edit and sign PDFs on any device, without having to download software.

If you’re applying for a new position or to rent a home, odds are that you’ll need to send several different PDFs in a single email. Fortunately, also offers PDF compression and merging services. 

Compressing multiple PDFs into a single file means putting the PDFs in a zip file with a smaller file size that can then be unzipped by the recipient to view the contents within. For more about file compression, check out our article on zipping and compressing PDFs

Merging PDFs means taking multiple separate PDF files and combining them into a single PDF file. The new PDF will have additional pages depending on how many different PDFs you’ve merged. If you or someone else has built a document in an external program, you may need to convert it to or from a PDF depending on what you intend to do with the file. Fortunately, also offers online file conversion services that allow you to convert different file formats to and from a PDF.