For a fillable form, you need to use Acrobat to change the tab order. Existing form fields can easily be moved up or down in the tab order list in Acrobat.
Thank you for responding. I'm actually using InDesign and was having trouble with setting the tab order. It just wasn't working. I think it had something to do with the way I created the fields. I just recreated them and it's working just find now.
Although you can't change the tab order in Indesign, it seems as though the order in which you create the form field remains consistent with the tab order in the PDF.
There's some misinformation going on here. There are actually 2 ways to
set the tab order in InDesign:
(1) Under the object menu: Object>Interactive>Set Tab Order
(2) Using the Articles panel: Drag your form fields into the Articles
panel, and set the tab order by rearranging them there.
Thanks for the clarification.