Hi Akansha,
There is no clarity about internet transfer of loan amount so its better to take a conservative view. About documentation, a simple letter mentioning the date,amount, terms of repayment would be enough.
In my view you should offer the loan to tax as income from other sources at normal rates (eg gift from friend>50000). This is because if it is shown as cash loan, the penalty is 100% and if it is classified u/s 68, the tax is flat 30%