In a 3PL model, an enterprise maintains management oversight, but outsources operations of transportation and logistics to a provider who may subcontract out some or all of the execution.
The 3PL model is where a manufacturer maintains oversight of their supply chain but outsources their transportation and logistics operations to a 3PL provider.
Most of the time, a 3PL will be receiving, handling, storing and delivering your goods. Usually, they will do so under the name of your business not theirs. This isn’t a large distinction for many companies but is an important one for some.