Insert File
Imports a file or a reference to a file into the current container field.
Insert File [Reference; <table::field>; “<filename>”]
Store only a reference instructs FileMaker Pro to store only a link to a file in the container field instead of the entire file. This option may reduce the size of your FileMaker Pro file, but if you move or delete the file being referenced, FileMaker Pro won't be able to display it.
Select Go to target field or click Specify to specify the container field to insert the file into.
Select Specify source file or click Specify to specify the file to be inserted. For information on creating file paths in FileMaker Pro, see Creating file paths.
This script step is:
You must specify a target field, click in a field, or use the Go to Field script step before performing this script step. If you do not specify a file to insert, FileMaker Pro displays a dialog box where the user can select a file.
Note  If there is no active container field on the layout where the script is being performed, Insert File returns an error code that can be captured with the Get(LastError) function.
Go to Field [Last Correspondence]
Insert File ["My_Letter.doc"]
Related topics 
Script steps reference (alphabetical list)
Script steps reference (category list)