Q. In an eCommerce website how the transaction are carried out and how do the payment gets deposited ?

Ans: Firstly you will need to setup an account with either paypal or Worldpay-futurepay (whatever you are using as your payment gateway). Then there is a gateway setup option which you will get at the time of installation of the shopping cart on your website. This is how the online shopping wizards checkout page will get linked to your paypal/Worldpay-futurepay account and the online payments done by your clients will get transferred to your account (either through paypal / Worldpay-futurepay, if your client selects paying through their paypal account) OR through credit card (if your clients select credit card option for paying the amount).