Shipowners possess, operate or charter (lease) ships and containers in their name.
Their role is to transport goods by sea from point A to point B in due time and safely.
They fit out the ship, which means that they man her with a crew, equip and supply her.
They provide everything necessary for operation and shipping.
Considering their role in the chain, they are in relation with most stakeholders: transport brokers, handlers, port authorities, etc.
In ports in which they are not directly operating, shipowners liaise directly with shipping agents / forwarding agents who act on their behalf and manage their interests.
Source: multiple Internet sources, specialized literature, testimonials (Pratic-Export, Pôle-emploi cards, Wikipedia, Onisep, CNRTL, Umep à la Page…)