Probably either one would do. Try it.
Thanks. That’s what I did and to answer my own question, I entered my husband‘s Social Security number and it got the routing number etc. said successful.
So then I decided to try my social Security number to be sure I got a check and it said that it was on file already and would be deposited to the bank account which was the right number. So just one of you has to enter the information if you file together.