If you are dressed, you are wearing clothes rather than being naked or wearing your nightclothes. If you get dressed, you put on your clothes.
He was fully dressed, including shoes.
他已穿戴整齐,包括鞋子。
If you are dressed in a particular way, you are wearing clothes of a particular colour or kind.
a tall thin woman dressed in black.
一个穿着黑色衣服、高高瘦瘦的女人。