Afer createInventoryItem call please execute createOffer call to add details of the listing, including price, eBay marketplace, eBay category, quantity, and listing polices (payment, fulfillment, and return policy)
and then execute publishOffer call to activate the offer on the eBay marketplace.
Please refer below doc to see the basic flow of using the Inventory API to publish the listing to eBay marketplace:
eBay Developer Support
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