If you add, remove, or move fields on a form, you'll want to change the form's tab order. A form's tab order determines the order in which you advance from one field to the next when you press the Tab key.
When a form is first created, the order of the fields determines the initial tab order. Even when you reposition the fields on a form, the form's tab order remains the same.
The Tab Order dialog box appears. The order of the fields in the list is the order in which you will advance from one field to the next when you press the Tab key. There are a couple of ways to change the tab order. The fast and easy way is to click the Auto Order button, which automatically rearranges the tab order to correspond with the order in which controls appear on the form.
If you don't see the fields listed, you may need to click Detail in the Section area of the dialog box.