In other words, Adobe Reader won't let you add text. What you need is a program that's a little more accommodating, PDF-wise. Try Foxit Reader 4.3, which allows you to add text to any PDF .

Just as in Adobe Acrobat, you can right-click any markup element and add a pop-up note. PDF-Xchange does not let you select text and replace it with new wording, as you can in Adobe Acrobat–and ...

PDF-XChange Pro — which is actually a bundle of three different tracker software products: ... To edit the text content of a PDF, ... You can also add 3D annotations and audio and video comments.