The height you'll be flying is what is known as attitude in aircraft speech; so when taking a helicopter ride expect to be flying anywhere between 1500ft to 2500ft.
Where you'll be taking a helicopter tour attitude matters as built up busy cities will result in you flying higher so its quieter for residents below.
Whereas flying over the Grand Canyon or other major national parts will allow you to fly high to see as far as the eye can see - to flying under 1000ft to see the wonder up close.
As it happens, you'll want to fly high as to take the best pictures and see all the sights.