Это поможет вам начать?Возможно, вы захотите добавить проверку ошибок ...
Option Explicit
Const FOLDER_PATH = "C:\TMP"
Dim fso, folder, file, newFileName
Set fso = CreateObject("Scripting.FileSystemObject")
Set folder = fso.GetFolder(FOLDER_PATH)
For Each file In folder.Files
newFileName = Year(Now) & Right("0" & Month(Now),2) & Right("0" & Day(Now),2) & "_" & file.Name
fso.MoveFile file.Path,file.ParentFolder.Path & "\" & newFileName
Next