If it is a modern bike with cantilever or V- brakes it is easy to open the brakes up-just remove the cable.
Older better quality bikes-maybe have a lever you can flip to open up the brakes a bit and get the wheel out of the calipers..
Now less expensive older caliper brakes bikes-center pull or sidepull- sometimes don't have a lever to loosen the brakes. In this case if your tires are skinny enough you can muscle them in and out-sometimes you have to let some air out which means carry a pump.In the old days-70's-I muscled the wheels in and out- of course I had the brakes adjusted a bit wide(not ideal) to allow this.
There is usually a way to get the wheel off without too much trouble even if it involves having the brakes adj in a less than ideal way-as long as you don't run out of lever travel on max efforts the brakes will work OK.
Charlie