Try Foxit Reader 4.3, which allows you to add text to any PDF. After installing the program, simply open your PDF in Foxit instead of Adobe Reader, then click Comments, Typewriter Tools ...

If you're still editing or creating a PDF, you can see, edit, and create alt text using your PDF-creation program. Visit Business Insider's Tech Reference library for more stories.

If PDF text or content disappears when editing, saving or printing files using Adobe, Foxit, etc, then this post will help you troubleshoot the issue.