When printing forms to PDF files, the PDF file can be named programmatically using the SET PRINT OPTION command. Specify the name of the PDF file in the path parameter. Here is an example (using an HFS path):

SET PRINT OPTION (9; 3; “Harddisk:Folder:SubFolder:DeptFinance.pdf”)
Print form([Department];”Finances”)
PAGE BREAK

For more information see:
https://www.4d.com/docs/CMU/CMU00733.HTM