Not exactly true, (other than the man-made elements) there are fusions that create elements
just above iron, but obviously a pittance compared to iron.
The fusion of iron consumes more energy than it releases, so it doesn't occur except in the case of supernova explosions, with their enormous neutron flux bombarding iron atoms to form heavier elements.
I've heard that heavier elements can form in the accretion disks of black holes, but that's the exception that proves the rule.
What where you referring to?