When it comes to data processing, Integration Services reads data from various sources, and writes them to their destinations, but usually some transformation of the data is needed in the meantime (according to the requirements, of course). SSIS can transform the data using its own transformation components. These can be used when placed in a Data Flow Task, connected with the source and destination components, or other transformation components.

So, here is the complete list of transformation components built into Integration Services 2012:

For more information about SSIS transformations, see the Integration Services Transformations topic in Books Online.