You will need to create an App with the permission to read and write orders. Then you will generate an access token, which you will add to the request by a header ‘X-Shopify-Access-Token’.
When you have that access token it is important that you keep it secret, and do not share it or add it to forum posts.
Just to clarify, we are trying to create an order and we are getting 0 errors.
The problem is, that even with a successful response, we are having some issues giving parameters to the specified fields.
Our company has many integrations with Shopify, we are familiar with your service, the problem is strictly related to the fields mentioned before.
I was not able to replicate the issue you saw with the data provided.
I would recommend reaching out to Partner support via the Partner Dashboard, with the request you are trying to make, the f description of the functionality you are seeing, and an example X-request-id header from an affected request.
They will be able to take a closer look at your specific requests.
Thanks!