However, ebook readers have limited hardware (most kindles cannot display colour for example) and the versions of HTML used are limited compared to those on a desktop computer or even a tablet computer. This has its good points and bad points. On the one had some accessibility techniques cannot be used with ebooks and other hand some are not applicable and so need not be worried about.
The approach I suggest, if you are producing basic text based notes, perhaps with some illustrations, is to create your content using the minimum of standard formatting. The document can be created in a word processor or a HTML editor. Use the standard headings, fonts, lists and the like. The content should then easily convert to most ebook formats. Depending on the ebook format used, you will be able to add colours and styles to make the content look prettier, but at least it will be readable on most devices. As an example see my "Demonstration of Using Moodle for Postgraduate Professional Education with eBooks and Smart phones".
If you have audio or video content I suggest not packaging it in the ebook, unless you are sure the student has broadband and a device which can view the video. Adding video can make the ebook file ten times larger (video can instead be supplied separately). As an example, Box Hill Institute of TAFE's excellent ebook for "Hand make timber joints" is 284 Mbytes. If the video is deleted from the ebook, the file reduces to 16 Mbytes, less than one tenth the size.
- Moodle Book Module: Moodle has its own simple ebook format called "Moodle Book Module". This uses the Moodle WYSIWYG HTML editor to create web p[ages which are book chapters. Moodle will convert the content to IMS Content Packages and also allow the student to export the content chaper or whole book as a web page. If you are creating content for Moodle this is a simple choice.
- IMS Content Package and SCORM: The, IMS Content Packages and the closely related SCORM packages consist of a zipped file containing HTML, CSS and other web format documents. SCORM is popular for vocational education.
- EPUB: Apple iPads have popularised the EPUB eBook format. If you are producing an ebook for a wide readership, this is the format you are likely to use.
- Tagged PDF: The version of "Tagged PDF" provides some accessibility features, implemented using XML. It might be useful for those committed to PDF, but for others, one of the HTML based ebook formats would be better.
- Kindle Format: Amazon Kindle ebooks use HTML (newer files use HTML5). This is the format you would use for publishing via Amazon.com. But t\note that Kindle devices can read PDF files as well and ordinary web pages (but not EPUB).