Log in to WinSMS.Mobi here and once logged in, click on 'Buy Credits'.

On the next step, enter the 'Quantity' of SMS credits you would like to purchase and then further click on 'Enable 1-Click'. 

Click on the slider to 'Agree' on allowing the secure Payment Gateway to save the credit card details to their secure server after a successful payment and the further click on 'Proceed'. 

On the next step you would need to fill in the required details and then click on 'Next'. 

After the payment has been approved, your WinSMS credits will be added to your account and the card details will now be stored on your account so that you can further do 1-Click Payments instead of having to always input the card details. 

Don't have a WinSMS account yet? Register your free trial account here.