Transfer bitcoins from one wallet to another We have started building a bitcoin exchange. Now we basically want to create and address that let users keep their bitcoin asset on that address and we will charge minimal fees to them when they withdraw it.

Now I have api key for my blockchain.info account now if we create an address for user let them deposit bitcoin and then transfer the assets to an address given by user, using api url below

http://localhost:3000/merchant/$guid/payment?password=$main_password&amp;second_password=$second_password&amp;to=$address&amp;amount=$amount&amp;from=$from&amp;fee=$fee

Where will the fee be received?

Please suggest
The fee you are referring to is the fee paid to the miners (not to you) for the transaction.  The miner (or mining pool) who is lucky enough to solve the block is going to receive all the fees from all of the transactions on that block.  It will be unknown who will receive the fee it until the block is solved. For more information, see Bitcoin Transaction Fees.  If you want them to pay you a fee, then you have to create a separate transaction for that.