How do I make sure my .pdf files are mobile friendly?

• The February 2019 article How to Get Your PDF Content into Google's Position Zero gives great information on optimizing a pdf.

  My question is: how do you make sure that a pdf file is mobile-friendly?

Answer:

How a .pdf is viewed on a mobile device depends on the device. An iPhone will automatically open PDF files into Safari, Chrome, or the Mail app — and it saves .pdf files to the iBooks app. Android, however depends on having the free Adobe Acrobat Reader app installed in order to open downloaded files. An Android alternative to Acrobat Reader is to use the free Google Drive app to open PDF files. So there's nothing special you can do to "make sure" a .pdf is mobile-viewable since the capability to view such files is a end user issue.

However, you CAN very often optimize a PDF file for download speed by optimizing the images. Surprisingly, people rarely seem to do so. We frequently see HUGE image file-sizes embedded within .pdfs – especially in product catalogs. So, if you aren't already doing so, this is one area where you can certainly improve a .pdf's mobile friendliness. Here's an online tool to help you do this.

Pro Tip: It's important that you know that PDF files pass PageRank. That means that you need to include outbound links to your website within all of your PDFs so that you share the authority that these files have. PDFs can be extremely authoritative documents and all too often businesses make them a dead end in regards to link juice. So be smart and add links and push readers to relevant pages.https://smallpdf.com/compress-pdf

...