You can download CAD Markup 2016.0 from our software library for free. This software is an intellectual property of Guthrie CAD/GIS Software Pty Ltd. CAD Markup lies within Photo & Graphics Tools, more precisely Viewers & Editors.
From the developer:
CAD Markup adds AutoCAD markup and PDF markup capabilities to CAD Viewer 2016. CAD and PDF drawings may be overlaid with text notes and other red-lining elements such as lines, boxes, circles, arrows, dimensions and area calculations, as well as images, and a user defined 'checked' stamp.
You may want to check out more software, such as CAD Design Icons, CAD Viewer or RED CAD EI, which might be related to CAD Markup.