The following annotations are available in the Comment ribbon.
Note: This is like a sticky note, and can be “glued” on top of the document page.
Text Box: Enter text phrases directly on pages with selectable font, style, color, and transparency. Callouts are special text boxes pointing to the place that a comment is made on.
Drawing: Enter graphic objects – or even a stamp, directly on pages with selectable shape, color, and other property settings.
Markup: Emphasize text parts on pages with highlight, cross-out, or underline. Also indicate suggested additions, deletions or changes to a document.
Attachment: Attach files, sounds, movies to the document.
Comment tools like Note, Text Box, Draw, Markup, and Attach File share many common properties. For details, see Annotation and Markup Object Properties.
Under security settings you can allow or prohibit commenting.
When you have reviewed a comment, choose Set Status from its shortcut menu to change its Review status and/or Migrate status. See Comments panel for details.
Annotations are stored in the PDF at a different level to the real PDF content. They allow shared document commenting. See also Print with Comments.
Note
To add new text you can also use the Typewriter tool. See Text Box to see the differences between these tools. Use the Edit Object tool to make minor editing changes to existing PDF text or objects, including typewriter text after the PDF has been saved. Annotations can be removed or turned into document objects with the command Flatten or removed by Removing Document Elements. They can be kept or dropped during optimization.