1. Business Formal - The most formal attire for work. At the far end of the spectrum this should be a pant or skirt suit with matching jacket and bottom, worn with a blouse or button up shirt and "sensible" close-toed shoes. At the other end of the spectrum you can mix and match the bottom and blazer, but take a cue from the other women in your office!
2. Business Casual - A step down from business formal, business casual to me usually means a skirt or trousers with a blouse and cardigan. No jeans.
3. Casual Work - This is more for the office where jeans are allowed. As long as you are wearing jeans on the bottom, you want to keep it professional looking everywhere else. This might mean close-toed shoes, a blouse and a cardigan or blazer. You can likely experiment more with shoe style and jewelry.