People with visual or cognitive impairments often rely on screenreader software to read out digital text to them, even if they have a degree of residual vision.
So ensure that manuals, feature lists etc. are provided in a way that can be accessed by screenreaders (ie. selectable HTML text divided up by appropriate H1/H2 headings, with descriptive alternative text supplied for images), rather than relying solely on printed materials or PhotoShop-exported PDFs.
PDFs are print documents and should not be used for communicating information electronically. While it is technically possible to make PDFs in a way that does not exclude people with screenreaders, doing so requires specific software and expertise. Using a more appropriate format, such as HTML, is a much better solution.