Im the US, when they're outside of the house, on the exterior, we call them shutters. Or, sometimes storm shutters as they are meant to protect the windows during storms. Unless you're in Florida or somewhere with hurricanes, they are almost always decorative and they don't actually function.
'Blinds' are on the inside of the house for blocking or allowing in sunlight; usually made of horizontal slats, although sometimes they can be vertical, and usually actuated by a string/cord. If it's just a big roll-up sheet type thing, we may often call it a 'window shade,' but you could also call it a blind.