Paste in Last Active Program

Question

Hello everyone. Here is my scenario:

I have a simple Windows Forms Application. There is a Form1 in it.

There is a textbox1 in Form1. "Some text" is written on this textbox.

I want that form to lose the focus when I click on the textbox and the last active program (for example Notepad or Chrome) will gain the focus and then that "some text" will be pasted on that program (ie Notepad or Chrome). How can I do that? Please note that I am a newbie. Thanks.