How to make enchantment Smelting Touch?

You can use this Tutorial:

https://youtu.be/CjogwIvQd6g

You could make a new block that looks and has the same properties, except it drops a REGULAR iron ingot if it is being mined with a tool that has smelting touch (just so you don't need to create a lot of recipes) and use that in your world. But that might only work if your making something like hypixel skyblock where it generates those blocks which you could add a plugin that generates blocks of your choice.

BUT, if you want to use it in a normal world you can add a procedure that if an iron or gold block is mined, it deletes the dropped item and instead then drops a smelted ingot at that same place. 

Sorry if i didn't explain it well (i am a bit more advanced than a newbie but i still can help people with things i know how to do)

Hopefully this works for you (: