StampPDF
The StampPDF tool lets you add a stamp—in the form of text or an image—to PDF files that change status
To define a text-type buffer, you can use it to populate a variable concatenation

Or simply an image by specifying the path (the image must be stored in the PDM repository):

By using the text type or the image path, the variables of the processed file can be used to automate the input, just click on the icon
and then enter the variables using the Variable concatenation
In the StampPDF interface, the user can easily change the font of the text that will be added by clicking on the icon 
You can also specify a color for the outline and the interior of the text:

To make the text transparent, the user can change the opacity value:

Finally, one last option allows you to set the stamp's position using horizontal and vertical offsets in millimeters; you can also apply a rotation when the text is centered on the page:

This gives us the following result:
It is also possible to locate the PDF files based on the source files used to generate them by applying a rule for calculating the file name and location.
For example, PDF files are automatically generated by DocPublication in a subfolder named "PDF":
If the task is run on the source files, then in this example you'll need to check the option that allows you to locate the PDF files and configure the search as follows:
For using variables, if TaskAction is run on the source file, the variables of the source file will be used, not the one of the PDF file.