setting file attributes on close

After closing:

    CreateObject("scripting.filesystemobject").getfile("E:\file.xls").attributes = 3

Put this code in the 'ThisWorkbook module in teh VBEditor (alt-F11)
The file will be Hidden & Readonly.

Private Sub Workbook_BeforeClose(Cancel As Boolean)
  If ThisWorkbook.Saved Then CreateObject("scripting.filesystemobject").getfile(ThisWorkbook.FullName).Attributes = 3
End Sub

You are correct, more options you'll find in the VBEditor's help, look for 'attributes'.

Function SetAttributes(sName As String, _
                       ByVal iAttr As VbFileAttribute, _
                       bSetClear As Boolean) As Boolean
    ' shg 2009-0202
    ' Requires a reference to Microsoft Scripting Runtime
    
    ' Sets or clears properties of the specified file or folder, e.g.,
    '       SetAttributes("C:\myPath\MyFile", vbReadOnly, False)
    '       SetAttributes("C:\myPath\MyFile", vbReadOnly + vbArchive, True)
    ' Returns True if successful

    Dim fso     As Scripting.FileSystemObject
    Dim obj     As Object           ' set to file or folder
    Dim jAttr   As Long             ' initial properties of the file or folder

    ' limit attributes to those that are r/w
    iAttr = iAttr And (vbReadOnly Or vbHidden Or vbSystem Or vbArchive)
    
    Set fso = New FileSystemObject
    
    If fso.FolderExists(sName) Then
        Set obj = fso.GetFolder(sName)
    
    ElseIf fso.FileExists(sName) Then
        Set obj = fso.GetFile(sName)
    
    Else
        Exit Function   '------------------------------------------------------>
    End If

    jAttr = obj.Attributes
    If bSetClear Then
        obj.Attributes = (jAttr Or iAttr)
        SetAttributes = (obj.Attributes And iAttr) = iAttr
    Else
        obj.Attributes = (jAttr And Not iAttr)
        SetAttributes = Not (obj.Attributes And iAttr)
    End If
End Function

Note that a reference is required.

Examples:

SetAttributes("C:\myPath\MyFile", vbReadOnly, False) ' clear read-only
SetAttributes ("C:\myPath\MyFile", vbReadOnly + vbArchive, True) ' set read-only and archive

See VBE help for Attributes Property for a list