how to pass data in DatagridView from Form1 to Form2 ?

Question

how to pass data in DatagridView from Form1 to Form2

when I click in Form 1 on search button to show me form 2

and when i selected row or more in DateGridView(in Form2)

it must add in form1(in DataGridView) ....but nothing add or change in form1 in DataGradview