This command is supposed to do what is said in the title, and the custom trade is an enchanted book. I am version 1.12, and this command does not work.
Also, since 1.11, entity ids are no longer like AreaAffectCloud, but like area_affect_cloud, and 1.13 just plain ignores them if they have uppercase letters, so you might want to get into a habit of that.
I don't think you can summon something with infinite health, but you can have a repeating command block that runs "/effect @e[type=Villager] regeneration 2 255 true" and they won't take any damage.
This command is supposed to do what is said in the title, and the custom trade is an enchanted book. I am version 1.12, and this command does not work.
You forgot a comma after the StoredEnchantments:
Also, since 1.11, entity ids are no longer like AreaAffectCloud, but like area_affect_cloud, and 1.13 just plain ignores them if they have uppercase letters, so you might want to get into a habit of that.
I don't think you can summon something with infinite health, but you can have a repeating command block that runs "/effect @e[type=Villager] regeneration 2 255 true" and they won't take any damage.
You should probably make it invulnerable instead {Invulnerable:1b}.