If you aren't sure whether you can read PDFs or not, please click here for a small PDF test file. If it displays - it is just plain text - then you already have the Reader (or similar). If not please read on.
If you do not have Acrobat Reader then you should probably consider getting it. A link below leads you to a free download from the Adobe website. However, if your computer is managed by someone else, for example the IT or computer department of your institution, you should consult them before trying to install the Adobe Reader. They would rather you checked with them first.
To get Adobe (formerly Acrobat) Reader please click the button above. This will open a new window and take you to the Adobe website, where you can download the software.
Please note: if you are offered extra software to download at the Adobe site, though it may be perfectly good software, it is beyond the scope of this article and we can only offer a blanket recommendation that you do not accept it.
PDFs are files in Portable Document Format, which was invented by Adobe Systems as a way of taking documents which were (usually) originally meant for printing and making them available on the web and in other electronic media. PDFs are close to the ideal of "electronic paper" because, if all is working well, when you view a PDF you are seeing something which is very close to what the author/publisher intended. They are capable of all sorts of clever and useful things but the most common use is to simply make available online a "printed" copy of a document.
The Adobe Reader, available free from Adobe (see button above), is the method by which PDF files are viewed. Once you have downloaded and installed it, clicking on a web page link to a PDF file should automatically start up the Adobe Reader so that you can view the file. It will usually start within your web browser, as a "plug-in", because it is usually well integrated with the browser. However, if someone sent you a PDF by email or on a disk or something you could use the Adobe Reader on its own to view or print the file.
Note: years ago, the Adobe Reader was called the Acrobat Reader. The term "Acrobat" is now only used for products which can create PDFs (see below), and not for the free reader software.
For more about PDFs please see Adobe's "Why PDF?" page
PDFs can be very useful for the author/publisher of a document. To make them you need the full version of Adobe Acrobat or a similar product - the free Reader just reads PDFs but can't make them. If you work for an organization you should check whether you already have something which creates PDFs, or if there is a licensing deal which would get you it cheaply. Click the link for more details of Acrobat.
Note - not just Adobe
Although Adobe created the PDF format, lots of other manufacturers produce software to exploit it. This article concentrates on the free Adobe Reader as it is perhaps the obvious choice but you should be aware that a web search would find alternative approaches.
A hint on saving, and easier access
In many cases it will be possible to take your own copy of the PDF file. The exact method will vary but you might try (a) open the file from your web browser and then save it, from within Adobe Reader, to your own chosen location; or (b) right-click the filename or link and then, from the popup menu which may appear, choose something like "Save Target As ... " or "Save Link As ...", and specify your chosen location. Then you would open the saved file from your own computer, not the online one. For some PDFs this latter approach may work better than just opening them directly in your browser.
If you have an old version of the Reader then it may be able to read our test PDF without trouble, but could be defeated by a more recent document which uses advanced features that are only supported by newer versions. If you are having trouble with a PDF document it is worth making sure that you have the latest version of the Reader.