In order to find netherite, you need to find ancient debris blocks, which only generate in the Nether dimension in Minecraft. You'll mostly find them at Y level 15 completely surrounded by blocks. You can use a pickaxe, TNT or bed explosions to find these blocks, but then you'll need a diamond or netherite pickaxe to mine and get them. Once you have four ancient debris, smelt them into netherite scrap. Combine the scrap with four gold ingots in the crafting table and you'll make a netherite ingot. You can also find these items in bastion remnant chests.