How to make an emerald sword on minecraft?

There are no emerald swords on the unmodded version, if you've seen some somewhere, they must have been added by a mod.

You don't without mods, but you can make Diamond Swords.
Emerald can make Emerald Blocks, but are mainly for trading with villagers.

Emerald is rarer than diamond anyways and Diamond tools are considered the best. I agree with th other 2 people it is a mod you just can't make on by choice.

Emerald tools and armor can't be crafted, and are in fact not in the game. The craftable tool types are wooden, stone, iron, gold, and diamond.

Emerald swords are only available in mods. The only basic (vanilla) use for Emeralds is trading to villagers, and to craft Emerald Blocks, which themselves are only decorations.

how do you get the mhighty morphin mod