How to: Set ToolTips for Controls on a Windows Form at Design Time
The dialog boxes and menu commands you see might differ from those described in Help depending on your active settings or edition. To change your settings, choose Import and Export Settings on the Tools menu. For more information, see Customizing Development Settings in Visual Studio.
To set a ToolTip programmatically
Add the control that will display the ToolTip.
To set a ToolTip in the designer
Add a ToolTip component to the form.
Select the control that will display the ToolTip, or add it to the form.
In the Properties window, set the ToolTip on ToolTip1 value to an appropriate string of text.