Hi Rohit
The answer to your questions is as follows.
1. Yes you can lend / borrow money on the basis of rate of interest. You can either borrow as an individual or institutional borrower. And you can lend money as a money lender for which you need to get money lenders license. And as a company you can lend as a Non Banking Finance Company after fullfilling all the mandatory legal compliances.
2. Yes you can give private loans to needy customers. But make sure you follow all the due procedure of law before doing it because without following the due procedure of law you will invite the wrath of Government Enforcement Agencies and Regulatory bodies. And also recovering loans from the borrower is also equally important.
3. So far as I know there is neither an individual financier or any finance company which provides loan online.
4. To know the procedure and documentation to be done to open your start up company you need to meet us in person and discuss to know what exactly is your requirement. You can mail us sheregar @ rediffmail . com