Yes dogs can digest raw vegetables and actually a lot of dog foods do contain raw vegetables mixed in with the dog food even though you cannot see the raw vegetables.
If you look on the ingredients of dog food it will show that some of the ingredients are common vegetables that us humans eat.
So yes you can feed your dog some raw vegetables if you want too and I've fed my dog raw vegetables quite a bit and it's healthy for them.
Sometimes I'll also feed the dog some steamed or cooked vegetables as well which my dog loves too.
But raw vegetables cut up in bite sized pieces are perfectly safe for your dog to eat.
Cats can even eat raw vegetables and cooked vegetables if they like them just be sure to cut the vegetables up small enough to make it easy for the dog to chew and digest.