How to define individual file name for each customer?

How to use serial letter fields to individual name PDF files in mail merge...
 

Click Mail Merge into Multiple Files. A dialog will be open.

After opening the dialog, define filename pattern as a combination of free text and document fields.

A field can be selected by clicking the + button on the right. After showing the field list - select a field from the list and then:

  • double click it or
  • click the Insert button at the bottom