Is there anyway that system can process a payment later on. when ever a customer do a payment using paypal on our website but transaction not processing immediately. we giving the customer a period of time, and when it past some number of days system automatically process the transaction. then only money reducing from customer's account. is this possible to do ? i'm using paypal API with codeignitor
It is possible, it is called "Payment Preapproval" which is part of PayPal Adaptive Payments. You can find more information here:
Basically you will need to redirect the user to PayPal in order to approve a payment which you can later process by yourself or automatically by PayPal.
If you know how to make a express checkout payment this topic will be very familiar.