hi @Heather_Benoit ,
it is an interesting question and my suggestion is maybe a bit different from what you had in mind and what others may suggest. It goes as follows
you create in your form as many fields for tags as you believe are reasonable, users use each field to fll in one tag (others may suggest to give in all tags seperated by a symbol like # in one field, but that is not what I have in mind) . In my example I have a form with 5 tag fields and I bring them together via a listcombine() in one column named allTags.
Next I create a button that transposes these values and add each one of them as a row to the tag table. This button is pressd by an automation when a form is submitted.
the set up is a bit of work on your side, but for the users it is simple.
I hope it helps, cheers, christiaan