minecraft-assets/assets/minecraft/advancements/story/enchant_item.json

{
    "display": {
        "icon": "minecraft:enchanted_book",
        "title": "Enchant an item"
    },
    "parent": "minecraft:story/mine_diamond",
    "criteria": {
        "enchanted_item": {
            "trigger": "minecraft:enchanted_item"
        }
    }
}