Once a PDF has been created and the text we see on the screen is actual text, and not the image of text contained in an image (See PDF Creation), our job is not quite done. We must be assured that users of assistive technology will be able to use the document in the same way that a fully sighted user will.
The most common error with PDF documents is the order in which assistive technology reads the contents. A PDF with reading order issues can make a document completely unusable to a user of assistive technology. There are a couple of ways of testing the reading order of a page:
Check to make sure that the document makes sense as you listen to it or as you read the plain text versions. If the document does not make sense then there are errors that need to be repaired. It is also important to note that any images you placed in the document are now gone and only the alternate descriptions of those images remain. Does your document still make sense with the descriptions of those images? If not you will need to adjust your description so that the meaning of the missing images is conveyed appropriately.