Arrows are ammunition for bows and dispensers. They can be modified to imbue status effects on players and mobs.
Normal Arrow
1 Flint + 1 Stick + 1 Feather = 4 Arrows
Spectral Arrow
The spectral arrow imbues the Glowing status effect for 10 seconds. The Glowing effect creates an outline of the target, which is visible through blocks, and colored based on the target's team (white by default). If a bow is enchanted with Infinity, spectral arrows will still be consumed.
4 Glowstone Dust + 1 Arrow = 2 Spectral Arrows
Tipped Arrows
Tipped arrows are arrows that imbue a potion effect when hitting a mob or player. The duration of the effect is 1⁄8 that of the corresponding potion, if applicable, and is not affected by the power of the arrow. The status effect is the same as the regular power effect for the potion. If a bow is enchanted with Infinity, tipped arrows will still be consumed.
8 Arrows + 1 of any Lingering Potion = 8 Arrows