Village Peeps
While you’re playing Minecraft, you might come across Villagers now and then. Villagers are peaceful creatures with large bald heads, large noses and green eyes. They form small communities all around the overworld and live in, as their name suggests, villages.

Villages
Villages appear in plain, savanna and desert biomes. They’re made up of various kinds of buildings: Wooden huts, houses, shops, libraries, farms, blacksmiths and churches.

All these buildings are connected by gravel roads, accompanied by wells and lamp posts. Sometimes the villages also house Iron Golems, large creatures made out of iron with faces that look a lot like those of villagers. They defend villages from zombies and other evil. They’re generally neutral towards players, as long as the player acts friendly. As soon as the player attacks an Iron Golem or a Villager, they will start to attack the player.

Trading Up
A way villagers can make themselves useful, is by trading items with you. You can sell items to them for emeralds, and you can buy items from them using emeralds.

Simply right-click a villager to open the trading GUI

Emeralds are basically the currency used by all villagers! You can trade with butchers, priests, blacksmiths, farmers and librarians. Each type of villager sells different kinds of items, mostly related to their profession. They will give you various offers, but only one of each. For example, a butcher would only have one offer to buy 16 pieces of raw pork, but never an offer of two different quantities of raw pork at the same time. Using trade, you can quickly acquire the items you need while selling off the items you no longer need!
Need emeralds? Check out: How To Find Emeralds In Minecraft.

Zombie Villagers
Villagers can also become zombiefied (or infected) in a zombie attack but luckily, there’s a way to cure them! You’ll need to isolate the zombie villager and then hit them with a splash potion of weakness and then give them a golden apple. After a few minutes of shaking and shuddering your zombie villager will return to normal!
 

How to tell a zombie villager apart from a normal villager (other than the green thing)