To enchant you need available gear that has the ability to be enchanted, and you need applicable weapon or armor shards.
In the beginning, you can earn some of these shards from a few side quests.
Talk to the Black Spirit and go to the enchantment tab. Put in your gear and shard, and in the beginning most basic equipment will have 100% success rate, which is good for the achievements. But if you're here for the late game haul. It might be better to save them for the gear you have that matters.