Selection.InsertFile (Word)

Inserts all or part of the specified file.

InsertFile (FileName, Range, ConfirmConversions, Link, Attachment)

Selection.Collapse Direction:=wdCollapseEnd 
Selection.InsertFile FileName:="C:\TEST.DOC", Link:=True

Arguments

The following argument is required

FileName (String) - The path and file name of the file to be inserted. If you don't specify a path, Word assumes the file is in the current folder.

Optional arguments

The following arguments are optional

Range (Range) - If the specified file is a Word document, this parameter refers to a bookmark. If the file is another type (for example, a Microsoft Excel worksheet), this parameter refers to a named range or a cell range (for example, R1C1:R3C4).

ConfirmConversions (Boolean) - True to have Word prompt you to confirm conversion when inserting files in formats other than the Word Document format.

Link (Boolean) - True to insert the file by using an INCLUDETEXT field.

Attachment (Boolean) - True to insert the file as an attachment to an email message.