What Is a PDF File?

How to open, edit, and convert PDF files

Developed by Adobe, a file with the .PDF file extension is a Portable Document Format file.

PDF files can contain not only images and text, but also interactive buttons, hyperlinks, embedded fonts, video, and more.

You'll often see product manuals, eBooks, flyers, job applications, scanned documents, brochures, and all sorts of other documents available in the PDF format. Web pages can even be saved to PDFs, in their full formatting, for later reference.

Because PDFs don't rely on the software that created them, nor on any particular operating system or hardware, they look the same no matter what device they're opened on.

An illustration of password protected PDFs in Windows 10

How to Open a PDF File

Most people head right to Adobe Acrobat Reader when they need to open a PDF. Adobe created the PDF standard and its program is certainly the most popular free PDF reader out there. It's completely fine to use, but we find it to be a somewhat bloated program with lots of features that you may never need or want to use.

Most web browsers, like both Chrome and Firefox, can open PDFs themselves. You may or may not need an add-on or extension to do it, but it's pretty handy to have one open automatically when you click a PDF link online.

We highly recommend SumatraPDF, Slim PDF Reader, or MuPDF if you're after something with a bit more features; all three are free. See our list of the best free PDF readers for more options.

How to Edit a PDF File

Adobe Acrobat is the most popular PDF editor, but Microsoft Word will do it, too. Other PDF editors also exist, like PhantomPDF and Nitro Pro, among others.

PDFescape, DocHub, and PDF Buddy are a few free-to-use online PDF editors that make it really easy to fill out forms, like ones you sometimes see on a job application or a tax form. Just upload your PDF to the website to do things like insert images, text, signatures, links, and more, and then download it back to your computer as a PDF.

A similar online PDF editor called Fill is great if you just need to add a signature to the PDF. It also supports including checkboxes, dates, and regular text, but you can't edit existing text with it or easily fill out forms.

See our Best Free PDF Editors list for a regularly updated collection of PDF editors if you're after something more than just form filling, like adding or removing text or images from your PDF.

Sejda online pdf editor
Sejda PDF Editor.

If you want to extract part of a PDF file as it's own, or split a PDF into several different individual documents, there are several ways to pull that off. See our Best PDF Splitter Tools & Methods for all the help you need to get that done.

How to Convert a PDF File

Most people wanting to convert a PDF file to some other format are interested in doing that so they can edit the contents of the PDF. Converting a PDF means that it will no longer be a .PDF, and instead will open in a program other than a PDF reader.

For example, converting a PDF to a Microsoft Word file (DOC and DOCX) lets you open the file not only in Word but also in other document editing programs like OpenOffice and LibreOffice. Using these types of programs to edit a converted PDF is probably a much more comfortable thing to do compared to an unfamiliar PDF editor.

If you instead want a non-PDF file to be a .PDF file, you can use a PDF creator. These types of tools can take things like images, eBooks, and Microsoft Word documents, and export them as PDF, which enables them to be opened in a PDF or eBook reader.

Saving or exporting from some format to PDF can be accomplished using a free PDF creator. Some even serve as a PDF printer, allowing you to virtually "print" pretty much any file to a .PDF file. In reality, it's just a simple way to convert pretty much anything to PDF. See How to Print to PDF for a full look at those options.

Chrome Save as PDF option
Printing a Web Page to PDF in Chrome.

Some of the programs from the links above can be used in both ways, meaning you can use them to convert PDFs to different formats as well as to create PDFs. Calibre is another example of a free program that supports converting to and from an eBook format.

Also, many of the programs mentioned can also merge multiple PDFs into one, extract out specific PDF pages, and save just the images from the PDF.

EasePDF is one example of an online PDF to Word converter that can save the file to DOCX.

See How to Convert PDF Files to JPG if you'd like your PDF file simply as an image, which can be handy if you're not sure if the person you're sending the PDF to has, or wants to install, a PDF reader.

EasyPDF.com is another online PDF converter that supports saving the PDF to a variety of formats so that it's compatible with Word, PowerPoint, Excel, or AutoCAD. You can also convert the PDF pages to GIFs or a single text file. PDFs can be loaded from Dropbox, Google Drive, or your computer. CleverPDF is a similar alternative.

Another conversion you can make is PDF to PPTX. If you use PDFConverter.com to convert the document, each page of the PDF will be split into separate slides that you can use in PowerPoint or any other presentation software that supports PPTX files.

See these Free File Conversion Programs and Online Services for other ways to convert a PDF file to some other file format, including image formats, HTML, SWF, MOBI, PDB, EPUB, TXT, and others.

How to Secure a PDF

Securing a PDF may include requiring a password to open it, as well as preventing someone from printing the PDF, copying its text, adding comments, inserting pages, and other things.

Some of the PDF creators and converters linked to from above, and others like PDFMate PDF Converter Free, PrimoPDF, FreePDF Creator, Soda PDF, and FoxyUtils, are some free applications out of many that can change these types of security options.

How to Crack a PDF Password or Unlock a PDF

Although protecting a PDF file with a password is recommended in some circumstances, you may end up forgetting what the password is, disabling access to your own file.

If you need to remove or recover the PDF owner password (the one that restricts certain activities) or PDF user password (the one that restricts opening) on a PDF file, use one of the tools in our Free PDF Password Remover Tools list.