Can you send a code when someone pays you?

[markbrenson]

Hi all, 

I'm looking for advice about how you would automatically send a code to someone when they pay for a service- is this possible on Paypal?

By way of example, someone days £x and they automatically get a message sent to them (or even better that appears on the screen at payment) that says

'Thanks for your payment, your code for tonight's online event is...'

Thanks in advance to anyone who knows how I could do that