Explain What are the APIs used in Order Management?

OE_ORDER_PUB is the main API in OM. Using this API all data manipulation (Inserts updates deletes can be performed on a Sales Order and it's attributes. Besides these certain other action requests such as applying holds attachments booking etc. can also be processed using the Sales Order API. After this in Shipping we have WSH_DELIVERIES_PUB.CREATE_UPDATE_DELIVERIES
for creating and updating deliveries for picked
lines WSH_DELIVERIES_PUB.DELIVERY_ACTION
for actions on created deliveries like PICK_RELEASE SHIP_CONFIRM