When you create some transformations, you do not have to create all of the ports manually. For example, you might create a Lookup transformation and reference a lookup table. If you view the transformation ports, you can see that the transformation has an output port for each column in the table that you referenced. You do not need to define those ports.
Create a port in the following ways:
Drag a port from another transformation.
When you drag a port from another transformation the Designer creates a port with the same properties, and it links the two ports.
Click the Add button on the Ports tab.
The Designer creates an empty port you can configure.