Before you merge the target document and data source file, it’s a good idea to preview the records to make sure that field data will appear properly when the information is merged. When you preview records, the Data Merge panel displays actual data from the data source file instead of the field placeholders. For example, instead of seeing <<Company>>, you might see Adobe Systems, Inc. You can use the navigation buttons on the Data Merge panel to cycle through the records.
If you find problems with any of the records, such as typographical errors or extra spaces, it is recommended that you edit the source file in its original application. (See About data source files.)