We’re just about to pay off the loan on our mobile home. The most recent correspondence we received from the mortage company included a phrase, “Payment should be made in certified funds or with title company check.”
What does this mean? Are we not permitted to send the company an ordinary bank check–as we have been doing monthly for years? Do they need a certified check? Does it require a special check form the mortgage company issues?
I’m clueless. 
Here is my best guess, if nobody else answers I’ll try to get a more complete (and possibly accurate) answer tomorrow when I get to work.
Certified funds refers to items such as cashier’s check, money orders, travelers checks, etc., where the face value is guaranteed by the issuing entity (you paid them to issue it, they promise to redeem it). Personal checks are not such a thing. A title company check is just a specialized form of certified funds, issued by a title company to be turned over to another title company.
I know when my parents sold their house, they were issued a title company check, which they immediately turned around and used on their new home.
I would guess that personal checks are acceptable for paying off your mortgage because title is actually going to be released with that payment. With a personal check there is more leeway for shenanigans that are present with a cashier’s check.