You can put a wider tire on your rear wheel without changing the bike handling too much. I wouldn't put a narrower tire on the back, so yif you want the 700x32, you should swap the front tire to the back and put the 32 up front. You should be able to order a 700x35 if you really want one.

Make sure your bike has clearance for a fatter tire on the frame & around the brake.

theoretically a 700x38 will have more drag than a 700x35, and may cushion the ride a bit - but you are probably not going to feel the difference.