There is not much to write about it. Short code to get Windows user name. Quite interesting is declaration for 32bit and 64bit systems. Unfortunately I’ve forgot source of code.

'  Declaration for 32bit and 64bit systems
#If VBA7 Then
    Declare PtrSafe Function Get_User_Name Lib "advapi32.dll" Alias _
    "GetUserNameA" (ByVal lpBuffer As String, _
    nSize As Long) As LongPtr
#Else
    Declare Function Get_User_Name Lib "advapi32.dll" Alias _
    "GetUserNameA" (ByVal lpBuffer As String, _
    nSize As Long) As Long
#End If

Sub UserName()
' Run this macro first

MsgBox GetUserName
End Sub

Function GetUserName() As String
' This is used by GetUserName() to find the current user's
' name from the API

Dim lpBuff As String * 25

Get_User_Name lpBuff, 25
GetUserName = Left(lpBuff, InStr(lpBuff, Chr(0)) - 1)
End Function