Text weight papers are designed for use on many types of common business documents, including newsletters, booklets, business correspondence, and more. They provide a good surface for printing and are more flexible than cover stock.
Cover weight papers are heavier, stiffer, and more durable than text papers. They're often used for printed pieces that require more bulk, such as booklet/report covers, posters, business cards, postcards, and the like.
Colored paper (including the colored bond, Astrobright, Astroparche, Royal fiber, and Royal linen) is available, although a little bit more unusual for color copies.