The Shipments API allows you to indicate that you have (partially) fulfilled an order that was created with the Orders API. This implicitly (partially) captures the authorized amount, which will then be settled to your balance.
The word “shipping” is used in the figurative sense here. It can also mean that a service was provided or digital content was delivered.
Refer to the Orders API guide for a step-by-step guide on implementing the Orders API and the Shipments API.