What is Form 1098?
A plain old Form 1098 (without any letter suffix) is a mortgage interest statement. It shows how much mortgage interest, points, and PMI you paid during the previous year. If you're also paying your real estate taxes (aka property taxes) through your lender, it'll show that too.
Your mortgage company should send you Form 1098 in late January or early February. You might also find your 1098 information on your January mortgage statement or bill.