Hi Gail E,
It depends on your goal.
Do you have a single line that you want to concentrate your research on?
If so, do you have a male relative from that line with that surname that
you could test? You may want to look into a Y-DNA test. Or if you are
working with someone else and you think you may have an ancestor in common,
you may want to look into a DNA test for that person.
Family Tree DNA Admin (volunteer)