You can add a tooltip to feature classes in a data set when importing the set. You do so when you configure the data. When you select its type, a Tooltip tab appears, giving you access to the Edit ToolTip window.
Click to display the Data Sources panel.
When importing data, open the configure panel. When you select a type, the Tooltip tab displays if tooltips are available for the selected type.
Click the Tooltip tab.
Enter any link for this tooltip.
See Add Links for information on entering link text.
Enter tooltip content.
See Create Tooltips for information on formatting Tooltip content.
Optionally, Click Preview to see what the Tooltip will look like. Click Return to Editor to revise or to finish creating tooltip.