Hello Yungandhar,
Thanks for posting your question to the A360 forum. Based on some of the descriptions you have posted I want to make sure you are asking about A360 and not something else.
A360 is not a dropbox type account, it's a collaboration tool that you can upload and download file to and from. We do have an "Edit on desktop" available on PC based systems, but it's only for office files like Word and Excel.
We also have A360 Drive Desktop Sync tool that ships with AutoCAD, AutoCAD LT, AutoCAD based verticals and Inventor, but that works with our A360 Drive product.
In this forum we help with questions on A360 and that is a collaboration based product that will allow you to create projects, invite people to the projects, share and view files in these projects and add comments to the files.
A360 Mobile has the ability to create an image of a file and allow you to markup the file with comments, leaders some very basic freehand tools.
You can learn more about A360 by checking out our Hangout. We have a getting started Hangout scheduled for next Wednesday from 11:00 to noon Pacific time. You can sign up for the Hangout at the following link.
http://autodesk360.com/hangoutYou can also view previous Hangout videos from that same location.
Also be sure to check out our BLOG posts on A360.
A360 Blog:
http://forums.autodesk.com/t5/a360-blog/bg-p/208If you are looking at using some other tool, can you let us know what that tool is and we can try to get you pointed in the right direction for help. If you are looking at A360, hopefully these suggestions above help and if you have more questions please just let us know.
Thanks again for posting to the A360 forum.