Ancient debris is one of the rarest ores in the game Minecraft. They lead to the netherite gear which is one of the strongest materials in the game. In order to find ancient debris you have to reach level 8 through 22 in the Nether. After reaching the level, if you mine through various blocks you will come across ancient debris. Use the diamond pickaxe to mine the ancient debris!
Ancient debris generates in the Nether in the form of mineral veins.They are commonly found in the y=15 level. If you want to gather ancient debris, first of all destroy the netherack with TNT explosions which can leave out the ancient debris as it has a high resistance. Another way is to exploit the mechanic in the Nether and The End that uses bed. This process is cheaper than the TNT explosion one. Go for the one you prefer!