Get Purchase invoice data in a selectable format

{
  "properties": {
    "external_key": {
      "type": "string",
      "description": "Used for accountants. The id you specified for the organization."
    },
    "external_user_id": {
      "type": "string",
      "description": "Used for the embedded portal retrieval service. The external_user_id you provided when the ShopAccount was created."
    },
    "guid": {
      "type": "string",
      "format": "uuid",
      "description": "The GUID of the invoice"
    },
    "legal_entity_id": {
      "type": "integer",
      "format": "int64",
      "description": "The id of the LegalEntity the invoice was received for."
    },
    "system_generated_primary_image": {
      "type": "boolean",
      "description": "Whether or not the document image (PDF) was generated by Storecove. If true, it means the invoice was received without any attachments and Storecove generated one for you. If false, the invoice will contain at least one attachment, which was received from the invoice sender."
    },
    "tax_system": {
      "type": "string",
      "description": "The tax system of the invoice. Either tax_line_percentages or tax_line_amounts. The first tax system means the invoice lines contain only the tax percentages and the tax amounts are included only in the tax subtotals at the invoice level and so are only calculated at the invoice level. The tax system tax_line_amounts means that in addition to the percentage, each invoice line also contains the tax amount. The tax subtotals at the invoice level are calculated as the sum of the tax of the invoice lines. The distinction between the two tax systems has has implications for rounding."
    },
    "ubl": {
      "type": "string",
      "description": "The Base64 encoded UBL invoice."
    }
  }
}