If your mortgage is through a traditional lender (bank, credit union, etc...), the form should be completed by them no later than Jan 31st each year. Most lenders will mail you a copy the first or second week of Feb, and many others will make them available for download for their online users around the same time. If you have not received a 1098 for your mortgage by mid-Feb, log into your mortgage servicer's website and look for "statements" or "tax forms."
If all else fails, call your lender or servicer and ask them to mail you a copy- their contact information should be on the last mortgage statement.
