Crafting magic items is not a skill or proficiency. It is a rare process that requires the right materials, the right conditions, and a reason.
Characters do not learn to craft magic items through training. Instead, the DN decides when creation is possible - usually involving rare ingredients, powerful magic, or an extraordinary source of energy.
Some items call for divine guidance, ancient formulas, or relic fragments. If characters pursue crafting, the DN decides what is required and what the result becomes - often serving as part of the adventure itself.