The loom is a block that is used to apply patterns on banners. This allows players to place a banner inside and customize it to their liking. It is also used as a shepherd's job block that is found in villages.
A loom (via screenshot)
Looms are only naturally generated in villages in the houses of shepherd villagers. You can pick up a loom by breaking it with or without any tools, but axes are recommended since they are the quickest. To craft a loom you will need two strings and two wood planks of any kind by placing them in a 2x2 formation with the planks on the bottom and strings on to will be able to make a loom.
Crafting a loom (via screenshot)
Right-clicking a loom will open its GUI, it has 3 slots for a banner, dye, and an optional banner pattern item. When a banner is put in, a list of 6 patterns will appear in the center part. Selecting a pattern or using a banner pattern on the list shows the preview of the banner after applying if a dye is present. To finish, the player must take the banner in the slot beneath the preview. The original banner and the dye disappear from their respective slots, but the banner pattern is not consumed.
Customizing a banner with a loom (via screenshot)
Looms are utility items that are used to customize banners by applying patterns to them. Looms are quite easy to craft making it a better method of obtaining them instead of looking for them in villages.
A. You will need 2 wooden planks of any kind and 2 pieces of string.
A. The leftmost slot if for your banner, the rightmost one is for the dye of your choice and the bottom one lets you put an optional banner pattern item.
A. Villagers that interact with a loom will have the shepherd’s job.