To remove/add or change description of payment method
Go to "Control Panel" -> "Payment methods" -> Check or Uncheck methods you want to use and click "Update"
To add Paypal
- scroll down to "Payment gateways" section
- select Paypal from the drop down list
(it's at the end of the list)
- click [Add]
To Sort payment methods
You can sort your payment methods by POS field. For example, if you want your customers to see Credit card processing before Paypal - enter "1" for Credit card and "2" for Paypal in POS field and click [Update]
*** Note: Make sure all Payment methods you enabled are set to use "HTTPS" protocol.