Once your data source file is created, you need to set up the target document and insert the fields from the data source file. The target document contains data-field placeholder text and graphics, such as the design that you want to appear on every postcard.

The target document includes fields from the data source with field placeholder text shown.

When you merge data, InDesign creates a new document that replaces the fields with the data you designated in the data source file. You can place data fields on either a master page or a document page.