Select the Type of Flow that you want to Process

You can select any of the flow that you want to process as you can append data in all the three types of flows

Select Append Data to contact Inside the Flow Builder

Drag and Drop the Append Data to Contact from the data services section

Append Data to Contact

Inside the flow builder select the add validation status from the append service. Also the validation status that you want to add.

Save

Click the save button to confirm the appending data to contact