WHY TOOL TIPS ARE IMPORTANT
You can make interactive form fields accessible to vision impaired users and users with mobility challenges by adding fillable fields to the PDF and by properly structuring it.
In addition, you can use the Tooltip field property to provide the user with information about the field or to provide instructions. For example, using the Tooltip property value, the screen reader user would hear “Check this box if you will be attending the luncheon.” Without the tooltip property, a screen reader simply provides the name of the form field (Checkbox 1), its type (Check Box), and its state (Unchecked). It would not be clear to someone listening to the form that they are indicating their desire to attend a luncheon.