hi there gpphani, welcome to the forums.
from the onset it's clear to see you're a traditional Windows/non-Apple person. Your questions are fully understandable and 'windows like'. i was there too at one time
For the first 3 questions see Apple's specs on their website. plain and simple. for the others -
1. I donot see a arrow mark in keyboard, how do i move cursor ?
correct, there isnt one. you use your finger for cursor movement. a bit fiddly, but you soon think nothing of it.
2. what is itunes for ?
itunes on your computer/desktop is a 'go-between' interface between your ipad and computer, which allows the transfer of media files and so forth. it allows you to copy and transfer photos, apps, music, movies etc etc. it also allows you to make backups of your ipad to the computer hard drive, allow you to update your ipad (or you can wirelessly do it of course), allows you to play movies and media on your computer, buys books, apps, songs etc etc. all sorts of things.
You also have an itunes store and app store facility available through your ipad itself. these are basically media shops that trade in a most similar fashion to the desk top version. all Apple products.
Peeps either hate or love itunes - thats up to you to make up your own mind
3. can i transfer a file over wifi to my pc ?
depends what the app is. some office apps allow wifi transfer en-mass. you can always copy things to drop-box or email things. itunes also allows certain file transfers.
4. I have a wired hp printer (HP Deskjet 1050 J410), how do i print any file?
dunno. you'll need to research the wifi printing forums we have here for that one. basically, as long as your printer is e-print compatible (my HP Photosmart is for instance) then there shouldnt be any issues. but there are usually alternatives.
5. how can i edit any microsoft (doc/docx/xls/ppt/pptx) file ?
again, search out the office app threads. Apple's own apps are Pages, Numbers and Keynote (the MS equivalent of Office). but i personally use Office2HD. others, for instance, use QuickOffice Pro HD or maybe Documents to Go. They all do most similar, but have their on strengths and weaknesses. takes your pick
6. Can I see different directories and contents in my ipad (like windows explorer in pc/android) ?
nope. Apple's iOS doesnt work this way. it's most different than what you're used to. it's a bit of a culture shock if you're new to it all. i clearly remember when i switched over a few years back. but you soon get into the swing of things. you fast get into the idea that file managers and directory reading isn't the idevice way. you just forget about it. Most apps have their own way of dealing with files and file transfer. iOS is basically very easy to use and understand and yes, it really does just work. as long as you're not angry and closed minded about the whole affair you'll love it. it does nothing more or less any other operating system offers.