For non-visual users, it is important that the PDF markup flows in the same logical order as the document is intended. This is quickly done through the Tags Panel
Any non-text element that conveys meaning must have a description, also known as alternate text (alt-text), associated with it.
In Acrobat, alt-text is essentially a tool-tip, therefore place your cursor over the object and you should see the alt-text pop up.
Check/edit reading order
Add Tooltip to a Form element
Edit a complex table
Edit a Simple Table
Open the Table Editor
Tag an image and add alt text
Every document must have a heading structure. Visually, we can identify by the look of text if it is a heading item. Non-visual users rely on the tags associated with text to identify them.
The Touch Up Reading Order Panel is used to add/edit tagged elements in a document. Having this panel open also assists in determining document structure and editing of alt-text and tables.