It helps when you supply all the required information and not drip feed it.

Yes the macro will do as you indicate because it looks for a string within the filename that matches the column 1. That string will be in all those examples that you quote. If the filenames are separated by spaces as you said earlier e.g.

Sealing Invoice ***XX1- Customer 740000.pdf

Then we can look instead at the number after the final space e.g.

Option Explicit

Sub Mail_Attachments()

Dim OutApp As Object
Dim OutMail As Object
Dim sAttach As String
Dim sPath As String
Dim iLastRow As Integer
Dim shtAddr As Worksheet
Dim xlSheet As Worksheet
Dim iRow As Long
Dim LastRow As Long
Dim vFname As Variant
Dim sFName As String

    Set xlSheet = ActiveWorkbook.Sheets("Email Body")
    xlSheet.Activate
    LastRow = xlSheet.Range("A" & xlSheet.Rows.Count).End(-4162).Row

    With Application
        .EnableEvents = False
        .ScreenUpdating = False
    End With

    Set OutApp = CreateObject("Outlook.Application")
    'LastRow = 3    'THIS LINE IS FOR TESTING ONLY!!!
    For iRow = 2 To LastRow 'Ignore the header row
        If LCase(xlSheet.Range("G" & iRow)) = "yes" Then
            sPath = xlSheet.Range("D" & iRow)
            Set OutMail = OutApp.CreateItem(0)
            On Error Resume Next
            With OutMail
                .To = xlSheet.Range("C" & iRow)
                .Subject = xlSheet.Range("E" & iRow)
                sAttach = Dir$(sPath & "*.pdf")
                While Len(sAttach) <> 0
                    vFname = Split(sAttach, Chr(32)) 'Split the filename by spaces
                    sFName = vFname(UBound(vFname)) 'Look at the last item
                    If sFName = xlSheet.Range("A" & iRow) & ".pdf" Then 'check if the last item matches the cell value + the extension
                        .attachments.Add sPath & sAttach
                    End If
                    sAttach = Dir$()
                    DoEvents
                Wend
                .HTMLBody = "<HTML><BODY>Please find invoice " & sAttach & " attached" _
                            & "<BR>" & "</HTML></BODY>"
                '        .Send   'or use .Display
                .Display
            End With
        End If
    Next iRow
    On Error GoTo 0

    With Application
        .EnableEvents = True
        .ScreenUpdating = True
    End With
    Set xlSheet = Nothing
    Set shtAddr = Nothing
    Set OutMail = Nothing
    Set OutApp = Nothing
End Sub