Here

Code:
Private Sub Command1_Click()
    
    Dim myData As String
    Dim br As Integer
    
    Open "C:\MyFile.txt" For Input As #1
    Open "C:\MyFile2.txt" For Output As #2
    Do Until EOF(1)
        Line Input #1, myData
        If (Right$(myData, 3) = "500") Then myData = "1," + myData
        If (Right$(myData, 3) = "460") Then myData = "2," + myData
            For br = 1 To Len(myData)
                If Mid$(myData, br, 1) = " " Then Mid$(myData, br, 1) = ","
            Next br
        Print #2, myData
    Loop
    Close #1, #2
    FileCopy "C:\MyFile2.txt", "C:\MyFile.txt"
    Kill "C:\MyFile2.txt"

End Sub