DNA has a tremendous amount of informatin stored in it, where did all that information come from?
It was inherited from the parents. If you go back far enough, then the answer becomes less known, and less about evolution and more about biochemistry.
So where did the information come from in biochemistry? Presumably from the laws of chemistry and physics. Some things do some things. Some of those things might inadvertantly allow for preferential reproductive success (there doesn't need to be information in the 'genome' on how to reproduce in order to reproduce, the laws of biochemistry and physics can do that work).
The answer therefore is: From the laws of physics. How did it get into the genome? Work was done. Where did the information from the laws of physics come from? Not a question for evolution.
Because there is no natural process known to science that creates coded information.
You asked where it came from, not for details of the process that lead to it getting there. You should be more specific. Anyway, the answer to the question:
by what process did information in the environment come to be represented in a nucelic acid?
Would be "I don't know, I wasn't there. There are some interesting ideas hypothesized by scientists that can achieve this goal, and some testing has occurred and some ideas remain unfalsified. Maybe it's one of them, or something like them. In general terms, and as I pointed out in Message 41: Work was done to achieve this end."