The Pass Through reader step passes the source data through the flow by reading it without modifying the records since the data can be modified by changing the configuration in the other available reader steps. When using this reader step, the data can only be modified by using mapper steps and not while its being read from a source step, trigger step, REST API or another flow.

It is automatically added whenever certain source steps are added to the flow. The Pass Through reader step can also be manually added before you add a source step. The image below illustrates how the Pass Through reader step looks.