Update 12 October 2021: Microsoft have stated that neither the organisation request described below, nor the publicly documented 'exportpdf' API are intended for public use, and that this public document (docs.microsoft.com/en-us/dynamics365/sales-enterprise/developer/exportpdf-api) is soon to be removed.
In October 2021, customers using the Organisation request from within a Plugin or Workflow started to see this error message:
“The private ExportPdfDocument request cannot be called from this plug-in because it has a different solution publisher."
This change was then reverted by Microsoft the following weekend in order to give customers time to find an alternative solution to this very common requirement.
If you think that |Microsoft should provide a publicly supported way of generating PDF's from Word Templates without having to first create a Word Document and save it in CRM, consider upvoting this idea:
Microsoft Idea · Make 'ExportPdfDocument' organisation request and 'exportPdf ' API action public (dynamics.com)