GroupDocs.Conversion allows you to apply a watermark to the converted document. You can set the following options for controlling how the watermark will be stamped in the converted document:
Background - specifies that the watermark is stamped as background. If the value is true, the watermark is laid at the bottom. By default is false and the watermark is laid on top.
To add a watermark, follow these steps:
Create an instance of the Converter class and pass the source document path as a constructor parameter.
Call the convert method of the Converter class instance and pass the filename of the converted document and the instance of ConvertOptions from the previous step.
The following code snippet shows how to apply a watermark to the output document: