As others before me, I've searched for documentation without luck. The main source of information is the GridExport file (pas and dfm) in the IW12FeaturesDemo program.
Not much explanation, but at least I could see how to use it. One of the things I was missing to begin with was the that the TIWAdvWebGridPDFIO.AdvWebGrid property should be set to the name of the actual grid one wants export. Fair enough, but with no such property in Object Inspector, and no description, it took a while to figure it out. Later I learned it is actually a published property of the ...EXCELIO component. I wonder why it is not in the ...PDFIO component.
The second parameter, I have not yet figured out what to do with. I see it is set with "WebApplication" in the FeatureDemo, but why, I do know. Being a parameter, I suppose it is intended as a possibility to use various values. It would be nice to know which though.
Also the 3rd parameter (true/false) of the PDFEXPORT function. No description of what it is for, and not used, nor described, in the features demo, it was only by chance I noticed as I was searching the forum for other issues:
With False it creates a file on disk, with the name and in the folder you define in the first parameter, e.g.: 'c:\documents\filename.pdf' or whatever URL you want. If you do not give any other that the filename, it is saved in the same folder as the EXE file. Not good if you as user do not have access to it...
With True (the default), it is showing the PDF onscreen in the browser. Very fine if you want to save it somewhere, but the way it is shown, leave no way of coming back to the page it was exported from, depending on which browser you use.
I would therefore propose the following enhancements for a coming update:
Add all relevant properties to the Object inspector, for both PDFIO and EXCELIO.
Create a (simple) documentation, describing the use of both PDFIO and EXCELIO, with all parameters and possible values, and maybe with some more detailed examples than the few lines in the FeaturesDemo.
I know it is difficult for the developers to find the time to document these things, but turn it around and try to imagine how much time is lost by the many who is trying to figure out how to use it, when there is no documentation available.