There is sometimes a misconception about how a custom dynamic stamp works in the PDF environment. Here is a short video that demonstrates how such a stamp gets applied:
As you can see, the custom dialog that collects the data that will be placed as part of the stamp pops up after the stamp is placed. Once all information is entered, and the “OK” button (how that button is labeled is up to the stamp’s implementation) is pressed, that data gets merged into the stamp and the stamp gets displayed. From that point on, that data can no longer be changed. It’s like placing a rubber stamp on a piece of paper. Once it’s there, it can no longer be modified. There are however a few things we can do with a PDF stamp: We can move the stamp, resize and rotate it – as shown in the video.
In the second part of the video, I am demonstrating how to use the “Stamp” tool button on the toolbar. In order to have this button available, you will need to add it to your toolbar. For more information about how to customize the Acrobat user interface, see for example here: http://blogs.adobe.com/acrolaw/2013/03/customizing-the-acrobat-xi-interface/
This article is not supposed to be a “tell all” story about dynamic stamps, I just wanted to demonstrate the basic workflow involved in placing a custom dynamic stamp. If you have questions about these types of stamps, please post in the comments.