How to Fight: the Wither
Jammy Lieber
The Wither is a tough mob to fight. Having more health than the Ender Dragon or iron golems, the Wither can be quite hard to fight if one is not prepared and taken the necessary precautions. First of all, Withers do not naturally spawn. You must get 4 soul sand from a Nether fortress and 3 wither skeleton skulls. Wither skeleton skulls are dropped by wither skeletons when killed, however, they have only a 2.5% chance of dropping it. You should use a looting enchantment sword if possible. Once you get your three skulls and four soul sand, find a place to spawn the wither. To spawn the wither, one needs to place the soul sand in a t-shaped arrangement (exactly like an iron golem's iron block arrangement). Then, the three wither skulls are placed on the top of each of the three soul sand blocks that are on the top layer. Beware however, once you place the last wither skeleton skull to complete the wither spawning arrangement, the wither will start to spawn. We will come back to this spawning process later. 
Supplies needed to fight the wither depend on strategy. The most strategic way requires these items: a full set of diamond armor (with a high protection enchantment, thorns may be useful but is not necessary), A sword with either sharpness or smite (fire aspect does not work on the wither), a bow with Power IV or V, punch, and infinity, Obviously an arrow (or many if you don't have the infinity enchantment), some instant health II splash potions, some strength II potions, and one or two enchanted golden apples. You will see how all of these will help in the following combat strategy.
Again, this is one of the infinitely possible combat strategies there are for fighting the wither. Make sure you are an ample distance from your house before spawning the wither. This mob has the potential to be incredibly destructive. When you make the arrangement for spawning the wither correctly as said above, you should see a mob appear that is black and has three heads. Also you will notice a boss health bar much similar to the Ender Dragon's health bar. You will also see the bar gradually filling up. At this time, get your sword, bow, apples, and potions in hand and equip your armor. You don't have much time. Run away as fast as you can and be a good distance away from the wither as the health bar fills up. When the bar is full, the wither lets out an explosion that destroys some of the terrain around it. You are now ready to start fighting. The wither attacks any mob that is not undead. When the wither starts to search for prey, it will look for any mob that meets its criteria for killing. Your strategy right now should be to use your bow and shoot arrows at him. If you hit him, he might see you and charge at you. He will shoot blue and black colored skulls that look like one of his many heads. If these projectiles hit you, they will deal a good amount of damage. Damage done is dependent on the difficulty. On normal, if one is hit with a wither skull, the wither effect may be inflicted. Wither is basically the same as poison except you can be killed if your health bar is low and turns your health bar back for its duration so it is slightly hard to see how much health you have. These skulls will deal terrain damage if they hit the ground. The rare, blue skull is prone to destroying blocks with a much higher block resistance, including obsidian. Continue to follow the pattern of shoot, flee, and repeat. Keep doing this to decrease his health. Use the health potions when necessary. When the health reaches half, you will notice a somewhat of a force field around it. The force field causes the wither to take less damage and makes it immune to arrows. At this point, your bow is rendered useless. Consume a golden apple and a strength potion and you have no choice but to charge in. That way, the Wither is within melee range. The wither will do no damage to you while you have regen from the apple. You will also do much more damage because of the strength potion. Hopefully, You can kill the wither in one go with the apple and potion. It should be enough. If you are successful in killing the wither, the wither will explode. The wither drops a small amount of experience and a single Nether star. This Nether star can be used to make a most desired beacon block.