Quiver
A quiver is an item that can store up to four stacks of arrows within a single inventory slot.
Obtaining
Putting a piece of leather in the bottom corner and middle of the crafting grid, and putting a piece of string in the top left gives one quiver. Combining any quiver with a dye of any kind will give a dyed quiver.
An apprentice fletcher will give a quiver for eleven emeralds.
Usage
Working similarly to a bundle, you can put in and take out arrows from the quiver any time in the inventory. It holds up to a max of four stacks of arrows, and the inventory GUI indicates how full each quiver is.
If a player has a bow in their inventory and their quiver has arrows, the bow will take arrows from the top of the quiver and shoot them. The bow will not shoot from the quiver if the quiver is empty.