Paying First, Then Completing Order

[plamenwolfmedia]

Hi there, 

I have a basic question regarding Payments in Shopify. We're using PayPal Express Checkout as our payment gateway. 

Right now, the way it is set it allows customers to 'Complete Order' first, and then they are redirected to PayPal where they can pay for their order. 

Is there a way to actually make the other way around - the client pays first and then he completes his order? 

I don't know if this is some PayPal policy or just a technical thing we aren't aware know to achieve. Any help is very much appreciated! 

Thank you.

Kind regards.