The program uses form variables CurrentControl and LastControl to keep track. It updates them in every control's GotFocus event handler.

Private CurrentControl As Control
Private LastControl As Control

' Return a control's name.
Private Function ControlName(ByVal ctl As Control) As String
Dim ctl_name As String
Dim ctl_index As Integer

    If ctl Is Nothing Then
        ControlName = "-"
    Else
        ctl_name = ctl.Name
        On Error Resume Next
        ctl_index = ctl.Index
        If Err.Number = 0 Then
            ' No error. The control has an index.
            ctl_name = ctl_name & _
                "(" & Format$(ctl_index) & ")"
        End If
        ControlName = ctl_name
    End If
End Function

Private Sub ShowControls()
    lblCurrentControl.Caption = ControlName(CurrentControl)
    lblLastControl.Caption = ControlName(LastControl)
End Sub

Private Sub Text1_GotFocus()
    Set LastControl = CurrentControl
    Set CurrentControl = Text1
    
    ShowControls
End Sub

Private Sub Text2_GotFocus()
    Set LastControl = CurrentControl
    Set CurrentControl = Text2
    
    ShowControls
End Sub

Private Sub Text3_GotFocus(Index As Integer)
    Set LastControl = CurrentControl
    Set CurrentControl = Text3(Index)

    ShowControls
End Sub