How do I create a custom stamp annotation?

Q:

Can u tell me how to create my own icon? I have seen some predefined
icons like Draft , sold , that is used for stamping.
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A:

To create your own icon for stamp annotation you would need to create
a custom appearance using ElementBuilder & ElementWriter. Then you can
use annot.SetAppearance() to associate the new appearance with an
annotation.

For examples of how to create custom appearances, you may want to
search this KB using the following keyword: "SetAppearance".

In case you simply want to stamp PDF pages with new content (instead
of creating a custom stamp annotation object), please see the
following FAQ:
  http://www.pdftron.com/net/faq.html#how_watermark

Also you may want to search this KB for the following article:
  "How can I stamp all PDF pages with a rotated and centered text
stamp"