She needs to use the same name that she has with the Social Security Administration (SSA). She needs to update SSA with her new name and to do that she’ll need to send SSA a copy of her marriage certificate if that is the the document that resulted in the name change. IRS matches what she puts on the return with SSA; if they do not match up the return may be unprocessable and that’s a headache. If she has not yet changed the name with SSA and is ready to file the return now then she ought to file the amended return with her old name as she has with SSA and then once that return is processed go and change her name with SSA. From that point forward, she’ll use her new married name. See the IRS page on name change after marriage or divorce for more information.

