curl --request POST \
  --url https://api.headlesscommerce.io/v1/admin/shipping_methods \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "name": "<string>",
  "price": 123,
  "description": "<string>",
  "free_shipping_threshold": 123,
  "metadata": {}
}
'

{
  "id": "<string>",
  "name": "<string>",
  "description": "<string>",
  "price": {
    "amount": 123,
    "currency": "<string>"
  },
  "free_shipping_threshold": {
    "amount": 123,
    "currency": "<string>"
  },
  "is_active": true,
  "position": 123
}