In short: yes.
PDFs are generally not a terribly optimisable format – if you can have content in HTML format (a normal webpage) then you should. But sometimes content lends itself to PDFs; you may have products that have datasheets in that format on top of their product descriptions, or articles with images and particular formatting and borders, and in these cases sometimes PDFs need to stay as PDFs.
However, you can still work on these PDFs to ensure they are working for your digital marketing and not against it. Google does index PDF content (some PDFs are purely image, but most are in a format that allows the search engines to read the text), so all that remains is for you to ensure you use every available method to give Google clear instructions on what the PDF is about and how it relates to your overall marketing objectives.
Firstly, as with all other formats online (webpages, text documents etc) the file-name offers an excellent opportunity to tell the search engines exactly what this file is about. So rename your file, ensure it has no spaces in the file-name (this is another good practice that applies to all other online files too)and make it relevant, concise and descriptive.
If we’re uploading a PDF that contains ‘Top Ten Tips for Increasing Your Sales’ we’d name the file something like: Top-10-Tips-Increasing-Sales.pdf
The hyphens are instead of spaces, and whereas you don’t need them there, I find they make a file-name easier to read for human users (often a good thing if people are looking at links to the file and trying to decide whether to click or not, for example).
You can also fill in a number of fields that exist in PDFs, which are these:
Title: This is what is sounds like, you want a concise title of the PDF. In the example above, the title might be ‘Top Ten Tips For Increasing Your Sales’
Author: The writer of the content, you may want to put an individual or your company. In the case of our example above it would be our MD ‘Nigel Wilkinson’.
Subject: A more general subject for the content. In the case of our example it would be ‘Ecommerce’ or perhaps ‘Ecommerce Marketing’.
Keywords: A few select highlighted words or phrases that are highly relevant to the content. So we’d be filling in ‘ecommerce, digital marketing, online shopping, seo, ppc’.
PDF Escape is one free piece of software that allows you to modify these fields, as you can see to the left.
In order to fill in these fields you need to be using a PDF editor such as Adobe Acrobat (not just Reader). There are some other applications that allow access to these fields too, so you may want to try a few trials, if you don’t want to use Acrobat.
Whereas you may initially have more important tasks for your SEO, if you have a smaller website and are now looking at advanced SEO techniques, it’s definitely worth your time to do at least some basic optimisation on your PDF files.