OpenCart supports various payment gateways which allow you to choose the payment processor that best suits your needs.
Once you select the payment processor and registered an account with it, you need to enable a payment module in your OpenCart ecommerce online store to start accepting payments from your customers.
To add or enable a new payment module, go to Extensions » Payments
Select the payment processor you like to enable for your store.
First of all you have to install the module. To do so, click on “Install” link.
As one demonstration, let us install the Paypal Payments Standard module. and then Fill in all the required information in order to make the chosen payment method work.
Click on “Save” button in the top right corner when you complete the settings.