Dolibarr has a module for restful APIs.
The API explorer seems to show all the CRUD tasks for each module like orders, stock and customer.
But to CREATE a record, the sample VALUE for the POST method shows as:
{ "request_data": [ "string" ] }
What are the specific field attributes that should go in here? Where can I look up the field requirements?

You should take a look at the attributes of the
Commandeclass: https://github.com/Dolibarr/dolibarr/blob/develop/htdocs/commande/class/commande.class.phpThe object should be something like this :