How to insert Vertical Scroll Bar in C#?

It's not clear what the problems is. You can always any available control, including ScrollBar: https://msdn.microsoft.com/en-us/library/system.windows.forms.scrollbar%28v=vs.110%29.aspx[^].

However, it's much more likely that you need a scroll bar already bound to some control behavior and shown automatically. For that purpose, you have to derive your scroll bar-enabled control, directly or indirectly, from the class System.Windows.Forms.ScrollableControl:
https://msdn.microsoft.com/en-us/library/system.windows.forms.scrollablecontrol%28v=vs.110%29.aspx[^].

In this case, the scrolling behavior is controlled mostly by the following properties:
https://msdn.microsoft.com/en-us/library/system.windows.forms.scrollablecontrol.autoscroll(v=vs.110).aspx[^],
https://msdn.microsoft.com/en-us/library/system.windows.forms.scrollablecontrol.autoscrollposition(v=vs.110).aspx[^],
https://msdn.microsoft.com/en-us/library/system.windows.forms.control.autoscrolloffset(v=vs.110).aspx[^],
https://msdn.microsoft.com/en-us/library/system.windows.forms.scrollablecontrol.autoscrollminsize(v=vs.110).aspx[^].

See also all other members named as …Scroll….

—SA