With the Customize dialog box open, right-click the toolbar button you want to specify a tip for, and then click Properties on the shortcut menu.
In the ScreenTip property box, type the tip that you want to display.
Notes
If you don't specify a custom ToolTip, Microsoft Access by default displays the text specified in the Caption property.
If the ToolTip doesn't appear when the mouse pointer rests over the button or combo box, verify that you have selected the Show ScreenTips On Toolbars box on the Options tab (Customize dialog box).