Outlook, new message composed, then add a specific file

When I composed an outgoing email message, THEN I want ta add a specific file (C:\path\file1.pdf) to this message.
Ho do I solve this issue?
Most of the VBA codes uses a new message + file. I want to add 1 fixed file.

The following will add the named file to the currently open message

Code:

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Sub AddAttachment()
'Graham Mayor - https://www.gmayor.com - Last updated - 18 May 2020
Const strPath As String = "C:\path\file1.pdf"
Dim olMsg As MailItem
    On Error Resume Next
    Select Case Outlook.Application.ActiveWindow.Class
        Case olInspector
            Set olMsg = ActiveInspector.currentItem
        Case Else
    End Select
    If TypeName(olMsg) = "MailItem" Then
        If FileExists(strPath) Then
            olMsg.Attachments.Add strPath
        Else
            Beep
            MsgBox "Attachment file not forund"
        End If
    Else
        Beep
        MsgBox "No mail item selected"
    End If
lbl_Exit:
    Exit Sub
End Sub

Private Function FileExists(strFullName As String) As Boolean
'Graham Mayor
'strFullName is the name with path of the file to check
Dim FSO As Object
    Set FSO = CreateObject("Scripting.FileSystemObject")
    If FSO.FileExists(strFullName) Then
        FileExists = True
    Else
        FileExists = False
    End If
lbl_Exit:
    Set FSO = Nothing
    Exit Function
End Function

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