More than one borrower.
If you and at least one other person (other than your spouse if you file a joint return) were liable for and paid interest on a mortgage that was for your home, and the other person received a Form 1098 showing the interest that was paid during the year, attach a statement to your return explaining this. Show how much of the interest each of you paid, and give the name and address of the person who received the form. Deduct your share of the interest on Schedule A (Form 1040), line 11, and write “See attached” to the right of that line.
P530 Instructions