Private Sub Print_But_Click()
On Error GoTo Err_Handler
Dim intFileNo As Integer
Dim txtFileName As String, LogMsg As String
    txtFileName = "\YourFilePath\"
    txtFileName = txtFileName & "YourFileName.txt"
'open text log file for append usage
    intFileNo = FreeFile()
    Open txtFileName For Append As #intFileNo
'Log date, time, and Windows UserName
    LogMsg = Format(Date) & " " & Format(Time) & ", User: " & Environ("UserName")
'carriage return/linefeed
    LogMsg = LogMsg & Chr(13) & Chr(10)
'Log whatever other data you want
    LogMsg = LogMsg & "YourDataChange = " & Your Field
'carriage return/linefeed
    LogMsg = LogMsg & Chr(13) & Chr(10)
...
'When done making LogMsg:
'carriage return/linefeeds (and/or anything else you want) to delineate between logging sessions
        LogMsg = LogMsg & Chr(13) & Chr(10) & Chr(13) & Chr(10) & Chr(13) & Chr(10)
        Print #intFileNo, LogMsg
    Close intFileNo                                                     'close text log file
DoCmd.RunCommand acCmdPrint
ExitSub:
    Exit Sub
Err_Handler:
    If Err.Number = 55 Then Resume Next                             'if text file already open
    If Err.Number = 75 Then
        MsgBox "Error opening text log file for logging. Logging failed."
        Resume Next                                                 'if text file open fails
    End If
    If Err.Number = 52 Then Resume Next                             'if text file write fails
    MsgBox ("Error #" & Err.Number & ": " & Err.Description)
    Resume ExitSub
End Sub