I assume that you are running this code from another Office application? If not you don't need to create an Outlook application as yolu are already in one.
You will need a function to identify the latest xml file in the folder, and if you want to retain your signature (and not running the code from Outlook) you will need the code indicated at the top of the macro to start Outlook properly. The code will pick the last modified xml file from your downloads folder.
Option Explicit
Private Sub MAIL_Click()
'Requires the code from http://www.rondebruin.nl/win/s1/outlook/openclose.htm
'Graham Mayor - http://www.gmayor.com - Last updated - 21 Jun 2018
Dim OApp As Object
Dim OMail As Object
Dim olInsp As Object
Dim wdDoc As Object
Dim oRng As Object
Dim signature As String
Dim strPath As String
Dim strAttach As String
strPath = Environ("USERPROFILE") & Chr(92) & "Downloads\"
strAttach = strPath & GetMostRecentFile(strPath, "xml")
Set OApp = OutlookApp()
Set OMail = OApp.CreateItem(0)
With OMail
.to = ""
.Subject = ""
.Display
Set olInsp = .GetInspector
Set wdDoc = olInsp.WordEditor
Set oRng = wdDoc.Range
oRng.Collapse 1
oRng.Text = "FYI"
.Attachments.Add strAttach
'.Send
End With
Set OMail = Nothing
Set OApp = Nothing
End Sub
Private Function GetMostRecentFile(strPath As String, strExt As String) As String
'Graham Mayor - http://www.gmayor.com - Last updated - 21 Jun 2018
Dim fso As Object
Dim oFile As Object
Dim oFolder As Object
Dim strfilename As String
Dim dteDate As Date
Dim iPos As Integer
On Error GoTo err_Handler
strExt = Replace(strExt, Chr(46), "")
Set fso = CreateObject("Scripting.FileSystemObject")
Set oFolder = fso.GetFolder(strPath)
dteDate = CDate("01/01/1900 01:01:01")
For Each oFile In oFolder.Files
iPos = InStrRev(oFile.Name, Chr(46)) + 1
If Mid(LCase(oFile.Name), iPos) = LCase(strExt) Then
If CDate(oFile.DateLastModified) > dteDate Then
dteDate = CDate(oFile.DateLastModified)
strfilename = oFile.Name
End If
End If
Next oFile
GetMostRecentFile = strfilename
lbl_Exit:
Set fso = Nothing
Set oFolder = Nothing
Set oFile = Nothing
Exit Function
err_Handler:
Err.Clear
GetMostRecentFile = ""
GoTo lbl_Exit
End Function