So the environment never causes a particular mutation to occur? Or, any mutation may occur in any environment?
Environment does indeed cause mutations (mutagens, cosmic rays, etc.) but the resultant mutations are random, not specifically targeted toward a result.
Use caution here. Any place in the genome is a mutation candidate, but, some areas are more robustly repaired than others. Also, outside the bacteria species, in the true multi-cellular creatures like trees, turtles and people, it is only a mutation in a germ-line cell that may get passed on to the offspring. A mutation in a somatic cell will have little to no effect on the organism (unless it's cancerous).
Regardless, all are random and have no predetermined value.