Artefacts in Minecraft Dungeons are powerful items that take the place of traditional abilities in other action-RPG games. Each one will give you access to a certain power, and you can swap them out as you see fit.
You can find Artefacts by finishing quests, killing enemies, opening chests, and searching through secret dungeons. When an Artefact drops, it will look like any other item, and you can interact with it to pick it up.
The Artefact will be placed in your Inventory, and you can then put it in your loadout by clicking on it, then clicking on one of the three Artefact boxes at the bottom left of the screen.
Unlike the rest of your gear, Artefacts cannot be given enhancements. They will drop in a range of levels and rarities, and these will combine to dictate how effective they are. Once the Aretact is placed in one of the relevant slots in the inventory, you can then use the prompted button on the HUD to use it.
Each Artefact will have a different effect and a set cooldown timer. Some will cause damage, while others might enhance one of your attacks. Some can heal you, or your whole party when used correctly.
Artefacts are very powerful and can make the difference between winning or losing a fight if you use them correctly. One of the more interesting aspects of Artefacts is that you can build synergies between them. If one Artefact slows enemies, while another channels heavy damage, then they will work very well together. You can also use them to shore up weaknesses in your item build.
If you are very tough, but slow, you can use an Artefact that will give you a boost of movement speed to move around levels faster. Part of the fun of Artefacts is finding different combinations that you enjoy using.