The issued B2G document contain all the fields twith data that reach to the Contracting Authority according to the EN16931 specifications

json definition with remarks:

{
    "IntegritySignature": "-",
    "IAPRSignPolicy": 2,
    "CurrencyCode": "EUR",
    "InvoiceTypeCode": "1.1",
    "SpecialInvoiceCategory": 0,
    "VariationType": 0,
    "DocumentType": "Τιμολόγιο - Δ.Αποστολής",
    "DocumentTypeCode": "ELB2G",
    "Series": "ΤΔΑ",
    "Number": "575",
    "DateIssued": "2023-06-27T00:00:00",
    "OrderNumbers": "",
    "OrderConfirmationNumber": "",
    "ReceivingAdviceNumber": "",
    "DispatchAdvice": "",
    "LotNumber": "",
    "GsisRelatedInvoices": [],
    "B2GDetails": {
        "ContractingAuthorityCode": "1000.E00512.0001", // Α.Α.Η.Τ MANDATORY - UNIQUE NUMBER OF THE CONTRACTING AUTHORITY
        "ContractingAuthority": "ΡΥΘΜΙΣΤΙΚΗ ΑΡΧΗ ΕΝΕΡΓΕΙΑΣ (ΡΑΕ)", //OFFICIAL NAME OF THE ORGANIZATION
        "ContractTypeCode": "3|2018ΕΠ06600057", // OTHER GOVERNENT | ADA OR PDE - MANDATORY(IF IT IS NOT AVAILABLE YOU CAN GIVE VALUE 3|0)
        "ContractReferenceCode": "20SYMV006467658" // ADAM (IF IT IS NOT AVAILABLE YOU CAN GIVE VALUE "0")
    },
    "Issuer": {
        "RegisteredName": "DEMO",
        "Vat": "EL123456789",
        "Phones": [
            "+301221121"
        ],
        "Emails": [
            "+301221121"
        ],
        "Address": {
            "CountryCode": "GR",
            "City": "ΑΘΗΝΑ",
            "Street": "Λεωφόρος Κύμης 132",
            "Postal": "42100"
            "Region": ""
        },
        "ContactPerson": "",
        "TaxRepresentativeName": "",
        "TaxRepresentativeCountryCode": "",
        "TaxRepresentativeVat": "",
        "Branch": "Εδρα",
        "PosId": "0",
        "BranchAddress": {}
    },
    "CounterParty": {
        "RegisteredName": "ΡΥΘΜΙΣΤΙΚΗ ΑΡΧΗ ΕΝΕΡΓΕΙΑΣ (ΡΑΕ)",
        "Vat": "099441906",
        "ContactPerson": "",
        "Phones": [
            "+301221121"
        ],
        "Emails": [
            "+301221121"
        ],
        "RegistrationNumber": "",
        "Address": {
            "CountryCode": "GR",
            "City": "ΑΘΗΝΑ",
            "Street": "Αθηνάς 63, Πλατεία Εθνικής Αντίστασης",
            "Postal": "10552"
            "Region": ""
        },
        "Code": "20"
    },
    "Recipient": {
        "RegisteredName": "ΡΥΘΜΙΣΤΙΚΗ ΑΡΧΗ ΕΝΕΡΓΕΙΑΣ (ΡΑΕ)",
        "Vat": "099441906",
        "ExternalCode": "",
        "Address": {
            "CountryCode": "GR",
            "City": "ΑΘΗΝΑ",
            "Street": "Αθηνάς 63, Πλατεία Εθνικής Αντίστασης",
            "Postal": "10552",
            "Region": ""
        }
    },
    "BillingContractor": {
        "RegisteredName": "",
        "Vat": "",
    }
    "AllowancesCharges": [],
    "Banks": [
        {
            "BicCode": "ERBKGRAA",
            "Name": "EUROBANK ERGASIAS",
            "Account": "Ergasias Bank Account",
            "IBAN": "GR Iban"
        }
    ],
    "DistributionDetails": {
        "InternalDocumentId": "436953964",
        "DeliveryDate": "",
        "StartDate": "",
        "dispatchDate": "",
        "DeliveryOriginDetails": {
            "Address": {},
            "Remarks": "Κεν/κό"
        },
        "DeliveryDestinationDetails": {
            "Address": {
                "City": "ΑΘΗΝΑ",
                "Street": "Αθηνάς 63, Πλατεία Εθνικής Αντίστασης",
                "Postal": "10552"
            }
        }
    },
    "PaymentDetails": {
        "paymentDate": "",
        "PaymentMethods": [
            {
                "PaymentMethodType": " 60 DAYS CREDIT",
                "PaymentMethodTypeCode": 5,
            }
        ]
    },
    "AdditionalDetails": {
        "TransmissionMethod": "A",
        "AvoidEmailGrouping": false
    },
    "Details": [
        {
            "LineNo": 1,
            "CountryCode": "",
            "Code": "21-001",
            "ItemCodification": "",
            "BuyerCode": "",
            "OrderID": "",
            "BeneficiaryAccount": "",
            "StartingDate": "",
            "ExpirationDate": "",
            "WithheldAmount": "",
            "WithheldPercentCategoryCode": "",
            "StampDutyAmount": "",
            "StampDutyPercentCategoryCode": "",
            "FeesAmount": "",
            "FeesPercentCategoryCode": "",
            "FeesPercentCategory": "",
            "OtherTaxesAmount": "",
            "OtherTaxesPercentCategory": "",
            "DeductionsAmount": "",
            "RelativeDocuments": "",
            "MeasurementUnit": "ΤΜΧ",
            "measurementUnitCodeEN": "H87", // MEASUREMENT UNIT CODE INDICATING PIECES -MANDATORY
            "CpvCode": "15511000-3", //CPV CODE OF GOOD/SERVICE/PROJECT BASED ON THE COMMON VOCABULARY FOR PUBLIC PROCUREMENT
            "Descriptions": [
                "Medicines"
            ],
            "SpecialFeatures": "",
            "MeasurementUnitCode": 1,
            "Quantity": 50,
            "AllowancesCharges": [
                {
                    "Description": "Cash Discount 1",
                    "type": 0, // { 0,1 }[ ALLOWANCE, CHARGE ]
                    "code": "1",
                    "underlyingValue": "116.90",
                    "percentage": "4.67",
                    "amount": "5.46"
                }
            ],
            "TotalNetValueBeforeTotalDiscount": 182.5,
            "AllowancesTotal": "",
            "LineApportionedDiscountValue": 0,
            "UnitPrice": 3.65,
            "CatalogUnitPrice": "",
            "NetTotalAfterInlineALCs": 182.5,
            "NetTotal": 182.5,
            "Total": 206.23,
            "VATTotal": 23.73,
            "VatCategory": "13",
            "VatCategoryCode": 2,
            "IsInformative": false,
            "IsHidden": false,
            "RecordTypeCode": 0,
            "Remarks": "",
            "IncomeClassification": {
                "Id": 0,
                "ClassificationTypeCode": "E3_561_001",
                "ClassificationCategoryCode": "category1_2",
                "Amount": 182.5
            }
        }
    ],
    "Taxes": [
        {
            "taxtypeCode": "",
        }
    ]
    "Summaries": {
        "TotalNetAmount": 182.5,
        "TotalVATAmount": 23.73,
        "TotalGrossValue": 206.23,
        "TotalPayableAmount": 206.23
    },
    "VatAnalysis": [
        {
            "Name": "13",
            "Percentage": 13,
            "VatAmount": 23.73,
            "UnderlyingValue": 182.5
        }
    ],
    "Banks": [
        {
            "Name": "",
            "BicCode": "",
        }
    ]
    "MiscellaneousData": {
        "Comments1": "",
        "Comments2": "",
    },
    "IsDelayed": false,
    "IsDelayedCode": 0
}

Important remarks

• DocumentTypeCode: This field must be setted to “ELB2G” so that to be declared that the issued document concerns a B2G transaction
  
• DispatchAdvice: This field must be filled if the information of a delivery note need to be diplayed on the Peppol Invoice and send to the Public entity.
  
• Issuer: Τhe details of the issuer are entered in this object and it is mandatory for all the invoices
  
• Counterparty: Τhe details of the counterparty are entered in this object. It is mandatory for the B2G invoices.
  
• Recipient: This field is being used in case that the expenditure concerns a different physical recipient or any department to which the responsibility has been delegated by law. Else the same value with “CounterParty”
  
• InternalDocumentId: It is a unique document number in the issuer’s system
  
• B2GDetails: This field is mandatory for all B2G documents and you find more information in the Features & Modules in B2G invoicing section
  
• PaymethodTypeCode: This code corresponds to the paragraph 8.12 of IAPR myDATA documentation
  
• TransmissionMethod: If this field has value “E”, an email with the invoice url will be sent to the email address that has being setted to the field “AccountingDepartmentEmails”. If it has value “A”, the invoice is only going to be archived.
  
• Details: In this object, each line is a product/service that you sell and all the details of it.
  
• RelativeDocuments: In this aray you can include all the Delivery Notesor ay other information if requested per line of products/services.
  
• MeasurementUnitCodeEN: This field is mandatory for B2G documents and it declares the measurement unit of the product
  
• CpvCode: This field is mandatory for B2G documents and it is a code of good/project/service based on the single classification system for public procurement from the European Union
  
• taxtypeCode: In this field you can fill the values regarding the different types of Taxes (Withheld,StampDuty etc) according the IPAR’s table 8.16
  
• Summaries: The summary ammounts
  
• VatAnalysis: The analysis of vat amounts by percentage
  
• Comments1: This field must be filled if you need to send general Invoice related information to the Public entity.
  
• IsDelayedCode: This field is used for heterochronous transmission. Value 0: Realtime, 1: Problem on the issuer side, 2: Problem on the IAPR side