Lets assume I want to send huge amount of money (in millions) from India to other country say United States and vice-versa and to be specific transferring online.
Transfer of Millions of USD in and out is not possible for Individuals. There are limits on how much money an individual Indian Ordinary Citizen can send or receive.
If an corporate wants to send money, depending on the services offered, they would have to initiate a SWIFT transaction. It typically takes 2-3 days for settlement of International wire.