1. A qvpp file is used to create the properties panel that you see with an extension. In QV 10, you needed to code this file yourself, and it could be tricky to do. In QV 11, this file is generated automatically based off of the Definition.xml file, so no extra coding is needed for most extensions. I'd suggest going this route, if possible.
2. Creating a qvpp file is easy, like I just mentioned. In terms of integrating D3 into an extension, this is something that's very possible, but there is a wide variety of things you can do with D3, so it's hard to answer without specific details. If you want to learn extension in QlikView generally, I would suggest starting here: Extensions. There are also templates you can use that are posted on community which would be a good place to start: Object Extension Templates. If you want to see actual code of extensions that leverage D3 with QlikView, you can find that at Qlik Branch. Here's a few projects that incorporated D3: http://branch.qlik.com/projects/showthread.php?218-Venn-Diagram-for-QlikView, http://branch.qlik.com/projects/showthread.php?143-d3-Chord-(Selectable), and http://branch.qlik.com/projects/showthread.php?139-Word-Cloud-Extension-using-D3.
There's also several d3 examples on Branch for Qlik Sense.
Thank you for clearing my doubt. All the materials are really good, I must have to appreciate for this. Currently I am working on Sunburst & MariMekko extension creation. But I guess all those QlikSense extensions we can't directly use in Qlikview. I tried but failed, if you help me it would be really awesome.
Again thank you.