PDF files may contain annotations; content that’s not part of the page but “floating” above it. Examples include highlighter marks and notes, but there are many types of PDF annotations. Even form fields are a class of annotation.
Just like any other content, annotations must be tagged in correct logical reading order and the tag(s) containing each annotation must accurately reflect the semantics at work.
For example, A footnote in the body of the text looks like this:
The superscript “1” is inside a Link Tag and both text run and Link are inside a Reference Tag.
The text from the footnote below (in the document) goes into a <Note> tag. Move the <Note> tag (and its contents) into the logical reading order of the document (after the <Reference> tag). If the footnote is used more than once in a page, move the <Note> tag to the bottom of the page.
A correctly tagged form annotation contains the text run(s) and the form field (in this case a text box) all inside a Form Tag:
A correctly tagged link is made up of a Link Tag containing the Link Annotation and the text runs that make up the link’s description:
To view annotations in the Logical Structure Editor or Verify and Remediate modes, use the Display Glyphs button and the Border button to view the annotation elements.
By selecting (drawing a box around) an annotation in the Physical view, the corresponding annotation in the Logical view will be highlighted.
You can delete annotations from the PDF by selecting it in the Logical view and pressing the delete key or using the toolbar Delete button.
Just as tags have properties, so do annotations. CommonLook PDF consolidates annotation properties management together with tag attributes management in the Properties tab. In particular ensure that the purpose of the annotation is included in the alt text attribute.