Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
Here is a starting point. Assuming you want to add it to all first level subfolders of the main folder, try this
Option Explicit
Sub AddSubfolder()
'Under tools, add reference to Microsoft Scripting Runtime
Dim FSO As Scripting.Filesystemobject
Dim RootFolder As Object
Dim SubFolder As Object
Dim myFolder As String
Dim myNewFolder As String
Set FSO = CreateObject("Scripting.FileSystemObject")
myFolder = "C:\Users\User.Name\Documents" 'Change to identify your main folder
Set RootFolder = FSO.GetFolder(myFolder)
For Each SubFolder In RootFolder.SubFolders
Debug.Print SubFolder.Path
myNewFolder = SubFolder.Path & "\2012"
If Not FSO.FolderExists(myNewFolder) Then
MkDir (myNewFolder)
End If
Next SubFolder
End Sub