Tagged PDF
Tagged PDF files contain metadata which describe the document structure and the order of the different document elements (e.g. pictures, text blocks, columns, titles). This makes it easier to extract text or graphics from PDF files, and helps screen readers to present the file content in the correct order. Accessibility standards may require PDF files to be tagged.
To create tagged PDF files, select this through a profile in the PDF Create Assistant.
In the 
Profile selection box, select Tagged PDF. The Tag PDF option is on by default in this predefined profile.
However you can also select any other profiles from the Profile selection box, and turn on the Tag PDF option in the PDF Create Profiles dialog box.
The tagging algorithm analyzes the content of the PDF file. It detects paragraphs, tables, cells of tables, and (raster) images. If the input file of the application is a PDF file with annotations and / or form fields, these will also be tagged. Typical tag names are <div> for a page and <p> for content judged to be a paragraph.
You can tag an existing PDF in PDF Professional using Tools > Tag PDF. If you use this command on a tagged PDF file the existing tags will be replaced.
Select a text object with the 
TouchUp Text tool to examine or modify the tag information assigned to it; right click for a shortcut menu, select Properties… for the TouchUp Properties dialog box and go to its Content and Tag panels.
Various tag-related operations are available in the Tags Navigation Panel. Use this to check whether paragraph detection was correct and to merge tags as necessary and add descriptive text to tagged items.
Tagging a PDF is a resource-instensive operation that can take several minutes. Press Esc to cancel a tagging process.
Notes
Using the tagging feature is not recommended with overlaid or watermarked files. Paragraph and table detection may fail in these cases.
Tagged PDF files cannot be generated when choosing the ScanSoft PDF Create! printer from a Print dialog box.
You can also create tagged PDF files from Word documents. For tagging options use the Tags tab of the Nuance PDF Settings for Word dialog box.