Scrolls are objects in the world of Naruto that serve many purposes.
The simplest scrolls in the series function as little more than paper to hold written information. Scrolls that are used in combat tend to serve as a way for the user to summon wide variety of things from people to objects to elements. Some examples of this would be:
Tenten, whose entire fighting style is based around summoning a wide range of weapons from a large scroll that she carries with her.
Sasori, who uses numerous scrolls located in his back to summon weapons and puppets.
Naruto, who used a large scroll during his battle with Pain to summon clones of himself.
Shikamaru, who summoned a large pool of water in his battle against Kakuzu and Hidan.