Acrobat serves up a complete set of commenting and markup tools for you to communicate your thoughts and edits when reviewing a PDF document. Comments can take the form of notes, stamps, highlighting of elements, and other types of markups for indicating text edits, such as strikethroughs for deletion. All of these tools are grouped together in the Commenting toolbar. In a review workflow these tools automatically appear, but you can access them at any time by choosing View > Toolbars > Commenting.
Here's a brief overview of the tools available in the Commenting toolbar and what they are used for:
Note tool: This is probably the most common tool used for commenting. With the tool selected, click or draw a box near or on the portion of the PDF you want to add a note comment to (think sticky notes for PDFs). Using the Select tool , you can reposition the note icon so that the note comment points to the area of interest.
Indicate Text Edits tools: Use these tools to edit text in the document. To indicate text that should be inserted, click between words or characters and start typing. To show where text should be deleted, select the text and then press the Delete or Backspace key. To indicate that text should be replaced, select the text and start typing over it.
Stamp tools: Use these tools much like you would their real world counterparts. Stamp a PDF to mark a document confidential or to indicate you have reviewed it. Click and hold on the Stamp tools icon to choose from the variety of preset stamps available. There are even dynamic stamps such as a name stamp and a time stamp. Once you've selected a stamp, click anywhere on the PDF to apply it.
Highlighter tools: The Highlighter tools include the Highlighter Text tool, the Cross-Out Text tool, and the Underline Text tool. Click and hold on the small arrow beside the Highlighter tools icon to choose the appropriate tool. Select text with any of these tools to call attention to it. You can then double-click the highlighted text to add a note.
Attach a File as a Comment tools: You can add a file or audio attachment using these tools. These comments are tracked in the review workflow like other comments and appear in the Comment List (Comments > Show Comments List). They will also appear in the Attachments tab along with the number of the page to which they were attached.