const options = {
  method: 'GET',
  headers: {'X-Spree-Seller-Id': '<x-spree-seller-id>', Authorization: 'Bearer <token>'}
};

fetch('http://{defaultHost}/api/v3/seller/delivery_zones', options)
  .then(res => res.json())
  .then(res => console.log(res))
  .catch(err => console.error(err));

curl --request GET \
  --url http://{defaultHost}/api/v3/seller/delivery_zones \
  --header 'Authorization: Bearer <token>' \
  --header 'X-Spree-Seller-Id: <x-spree-seller-id>'

{
  "data": [
    {
      "id": "dz_UkLWZg9DAJ",
      "name": "Domestic",
      "description": "Maxime illum debitis veritatis porro accusantium laudantium omnis.",
      "delivery_profile_id": "fp_gbHJdmfrXB"
    }
  ],
  "meta": {
    "page": 1,
    "limit": 25,
    "count": 1,
    "pages": 1,
    "from": 1,
    "to": 1,
    "in": 1,
    "previous": null,
    "next": null
  }
}