it off by hand.
on the other side of it, some bell peppers develop their color before turning to a red hue. with those you must pick them in a similar way as you would a green pepper before turning red. some of those that color in immature states are those that are purple, brown, orange, white, lilac and yellow.
harvesting hot peppers is about the same as for sweet bell peppers, but you do need to be aware of a couple of things.
first, a person should always wear rubber or plastic gloves when handling hot peppers. as much as you're able to, somehow remind yourself not to touch any bare skin 