curl --request GET \
  --url https://api.sandbox.tesouro.com/finops/v1/receivables/required-fields \
  --header 'Authorization: Bearer <token>' \
  --header 'x-finops-version: <x-finops-version>' \
  --header 'x-organization-id: <x-organization-id>'

{
  "counterpart": {
    "tax_id": {
      "description": "The counterpart's taxpayer identification number or tax ID. For identification purposes, this field may be required for counterparts that are not VAT-registered.",
      "required": false
    },
    "vat_id": {
      "description": "The counterpart's VAT (Value Added Tax) identification number. This field is required for counterparts that are VAT-registered.",
      "required": false
    }
  },
  "entity": {
    "tax_id": {
      "description": "The entity's taxpayer identification number or tax ID. This field is required for entities that are non-VAT registered.",
      "required": false
    },
    "vat_id": {
      "description": "The entity's VAT (Value Added Tax) identification number. This field is required for entities that are VAT-registered.",
      "required": false
    }
  },
  "line_item": {
    "measure_unit": {
      "description": "Unit used to measure the quantity of the product (e.g. items, meters, kilograms)",
      "required": false
    },
    "tax_rate_value": {
      "description": "Percent minor units. Example: 12.5% is 1250. This field is only required on invoices issued by entities in the US, Pakistan, and other unsupported countries.",
      "required": false
    },
    "vat_rate_id": {
      "description": "Unique identifier of the vat rate object. This field is required for all entities in supported countries except the US and Pakistan.",
      "required": false
    }
  }
}