Yes it's normal to have some standing water in a dishwasher.
Dishwasher machines do not drain down all the water and normally leaves a few inches of standing water in the bottom of the dishwasher.
My own dishwasher always leaves at least an inch of water in the bottom and it's normal and doesn't mean that anything is wrong with your dishwasher.
If it's leaving more than a few inches of water in the bottom of the dishwasher than you could have a partially clogged drain line or the pump may be getting weak and not allowing the rest of the water to get out of the dishwasher.
But having a few inches of water left in the dishwasher is perfectly okay and normal.
If you want to remove the standing water from the dishwasher you can use a hand water pump or use a Shop Vac to suck the water out especially if you're not gonna be using the dishwasher for awhile.
I always suck the standing water out of the dishwasher if I'm gonna be away from home for a week or longer on vacation to prevent the water from growing mold and other bacteria in it.