Add Order Information when Creating Order via API

I am using Rest API to create orders. How do I add order field information to the order via the API? Are there any notes/documentation or anything? I can get orders to go through and calculate tax etc but can’t seem to find a way to edit order field info… Please help.

When you add an Order Item you can add a Description property to it, but there isn’t currently a PATCH/PUT on Order Items, so if you need to update it after-the-fact you will have to delete the Order Item then re-add it.