The Shipping Offers API provides everything you need to display an offer or quote, for Shipping Protection to your customers. Shipping Offers consist of two parts: the Quote and the Config.

Quote contains the total premium, i.e. the price you will charge the customer, for the specified cart
Config contains information about how to present the shipping protection offer, as well as the marketing and compliance text to provide to the customer during the shipping protection purchase process.

There are two main methods of offering shipping protection to your customers.

Extend Choice, which means the customer can opt in or opt out of a shipping protection offer. Within Extend Choice, OPT_IN means that the offer is NOT selected by default, and the customer must choose to add it. OPT_OUT means that the offer is selected by default and will be included in the order unless the customer deselects it.
Extend Complete, which means that shipping protection is included in every eligible order automatically, at the merchant’s choice (OPT_MERCHANT).

These methods are represented in the Shipping Offers API Config as attachBehavior, with possible values OPT_IN, OPT_OUT, or OPT_MERCHANT.