Northern Trail Outfitters (NTO) has been using B2C Commerce and Service cloud for the past...

To enable transactional messages from B2C Commerce to Marketing Cloud, you need to configure API integration credentials in Marketing Cloud, which will generate an authentication token and a REST endpoint for your account. Then, you need to implement a server-side API callout in B2C Commerce for each of the required emails, which will use the authentication token and the REST endpoint to send the email data to Marketing Cloud. Finally, you need to configure a Transactional Messaging API in Marketing Cloud, which will allow you to create and manage transactional messages using REST API calls. You also need to use a transactional send classification for each of the required emails, which will indicate that the email is not subject to unsubscribe rules.

References:

[API Integration]

[Transactional Messaging API]

[Send Classifications]