The Letter.SaveAs() method prints Layout_Name to file in PDF, HTML, RTF, or TXT formats. If no format is specified, the PDF format is used.
If you specify an optional Filter_Expression, the only records matching the filter are printed. (In addition to the filter specified here, the layout may have a filter defined within the layout definition).
The layout is printed to Output_Filename. If Output_Filename is not specified, the layout is printed to a file with the same name as the Layout_Name in the same folder as the database.
For more information and detailed description of parameters, see Report.SaveAs Function.