how to avoid penalty while making spousal contribution to roth for no income spouse

Husband is retired so no job related income.   I, while working, contributed 6500 to his Roth.  In Turbo tax, when I enter the 6500 into his Roth account, I get a message that he has incurred a penalty (because of his no income).   Where can I indicate this was a spousal contribution?   or how to remove the penalty?