SoloCodigo

Si entiendo bien tu inquietud lo que debes hacer es insertar un TabControl en un formulario y tres botones fuera del tab control y en el formulario programa el siguiente código:
____________________________________________________________________________
Public Class Form1

    Private Sub CrearTextBox(ByVal EnDonde As Integer)
        Dim NewTextBox As New TextBox
        NewTextBox.Name = "TxtPrueba"
        NewTextBox.Text = "como te quedó el ojo"
        NewTextBox.Location = New Point(10, 10)
        If EnDonde = 1 Then
            TabControl1.TabPages(0).Controls.Add(NewTextBox)
        Else
            TabControl1.TabPages(1).Controls.Add(NewTextBox)
        End If
    End Sub
____________________________________________________________________________
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        CrearTextBox(1)
    End Sub
____________________________________________________________________________
    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        CrearTextBox(2)
    End Sub
____________________________________________________________________________
    Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
        Dim Var As New Control
        Dim i As Integer
        For i = 0 To TabControl1.TabCount - 1
            For Each Var In TabControl1.TabPages(i).Controls
                If TypeOf Var Is TextBox Then
                    Var.Text = ""
                End If
            Next
        Next
    End Sub
____________________________________________________________________________
   
End Class

Espero que te sirva el aporte