No one denies that organisms change,
what the argument is is
WHERE DOES THE “NEW” INFORMATION COME FROM?
Two assumptions - it was always there since the organism’s original ancestor was created
or, it appeared through mistakes and random modifications.
I like the “post turtle” analogy, myself.
We know all we need to know about the nature of both fenceposts and turtles to know that if we find a turtle balanced on a fencepost, someone had to put it there.
Claiming some as yet undiscovered mechanism allowed the turtle to perch on the fencepost through undirected means is intellectually dishonest.