How to disable billing address in Drupal Commerce while using Paypal WPS I'm setting up a very simple online shop for a charity. They'll use Paypal WPS and don't want to collect customer's billing address as those will be entered in Paypal anyway. Is there a way to remove the billing address from Drupal Commerce.

I'm only using PayPal, so the aforementioned answer doesn't apply.
If you do not need Billing Address section at all, it should be as simple as dragging Billing Information under disabled from any of checkout/review step. 
Go to page 'admin/commerce/config/checkout' in order to disable Billing Section.

If you want Billing Address section to vanish conditionally based on payment method opted(in case you have multiple way of payment) then it is already answered here by Ryan himself.