Hi Sandeep,
There are a few different ways to go about doing this depending on the exact behavior you desire.
If you are looking for the user to be able to select, copy, and paste text then I would suggest taking a look at the following links:
How to: Select Text in the Windows Forms TextBox Control
Cut, Copy, Paste and Undo in VB .NET
The first link explains how to select text based on a user's action - in this case, when the textbox initially gains focus. The second link will then explain how you can similarly create copy/paste functionality for the user from a button or other source.
The above shows how you would accomplish a copy if you wanted the user to be able to copy at runtime. However, if you are looking to programmatically take the text in your textBox and copy it into another field, you can do this using the following code:
textBox1.Text = "Test";
string test = textBox1.Text;
The first line is setting the text value and the second line is taking the value and putting it into the string 'test'.
I hope this helps, good luck on your project!
Regards,
Trey C.
