There are a couple of issues that need attention in your code, but for the main part, the document you have created from your template can be saved as a temporary file, attached to the message and then deleted e.g. as follows. Personally I would use the code at
Test if Outlook is open and open Outlook with VBA to open/start Outlook, but this will work with some minor changes.
Code:
Private Sub CommandButton1_Click()
'Graham Mayor - https://www.gmayor.com - Last updated - 27 Apr 2020
Dim OL As Object
Dim olInsp As Object
Dim EmailItem As Object
Dim Doc As Document
Dim wdDoc As Document
Dim oRng As Range
Dim strPath As String
strPath = Environ("TEMP") & "\Filename.docx" 'change name as required
Application.ScreenUpdating = False
Set OL = CreateObject("Outlook.Application")
Set EmailItem = OL.CreateItem(0)
Set Doc = ActiveDocument
Doc.SaveAs2 FileName:=strPath, FileFormat:=12, AddToRecentFiles:=False
With EmailItem
.Subject = "ENTER SUBJECT LINE HERE"
.To = "ENTER RECIPIENT EMAIL HERE"
'.CC = "ENTER A CC EMAIL ADDRESS AND REMOVE COMMENT OUT TO MAKE LIVE"
.Importance = 2
Set olInsp = .GetInspector
Set wdDoc = olInsp.WordEditor
Set oRng = wdDoc.Range
oRng.Collapse 1
.Display 'This line is required
oRng.Text = "ENTER MESSAGE HERE" '& vbCrLf & _
'"BODY SECND LINE" & vbCrLf & _
'"BODY THIRD LINE"
.Attachments.Add strPath
.Send
End With
Doc.Close 0
Kill strPath
Application.ScreenUpdating = True
Set OL = Nothing
Set EmailItem = Nothing
Set olInsp = Nothing
Set wdDoc = Nothing
Set oRng = Nothing
End Sub