Microsoft Office products, including Word, Powerpoint and Excel, have extremely useful in-built accessibility checking functionality. This will check to see whether alt-text has been added to images, whether the structure of a document is accessible and headers are in place, as well as more specific aspects of accessibility in, for example, presentation slides and spreadsheets.
The University of Kent provided extensive and detailed information on providing accessible formats. This includes specific guidance on:
We would highly recommend the pages from the University of Kent when considering the accessibility of specific documents, as well as specific content such as graphs and media content.