Can my customers copy the Billing Address fields to the Card Address?

Yes, they can. To enable the Same as Billing Address checkbox on your payment pages:

• Click the Settings icon in the upper right corner of the window.
• Select Templates.
• Hover over a template to display available actions.
• Click Edit to open the customization menu.
• Click to expand the Customer Information and Payment Information sections.
• Make sure that all the mandatory fields under Billing Address are exactly the same under Card Address as well.