Add a Form1 and set this formproperty: IsMdiContainer property to True.
Add a Form2 and and use this code:
Dim frm2 As New Form2 frm2.MdiParent = Me frm2.Show()
Where do I put this code , in form1 or in form2
What is the event that put him in it
You can use this code in a buttonclick event in the parentform.