Create an item fulfillment from a sales order record through REST API.

 POST https://<accountID>/services/rest/record/v1/salesorder/{{SALES_ORDER_ID}}/!transform/itemFulfillment
{
    "item":{
       "items":[
          {
            "orderLine":1,
            "location":6,
            "itemreceive": true
          }
          {
            "orderLine": 3
            "location": 6,
            "itemreceive": false
          }
       ]
    }
}