Create

//  Create a Map to store all the data of a Invoice
List<Object> invoiceList = new List<Object>();
Map<String, Object> invoiceMap = new Map<String, Object>();
    invoiceMap.put('TxnDate', '2021/08/11');
    invoiceMap.put('DueDate', '2021/09/11');
    invoiceMap.put('DocNumber', 'Inv-1201');
    invoiceMap.put('ExchangeRate', 1.0);

    //  Initializing the Invoice Custom Fields
    List<Object> customFieldList = new List<Object>();
        Map<String, Object> customFiel1dMap = new Map<String, Object>(); 
        customFiel1dMap.put('DefinitionId','1');
        customFiel1dMap.put('Type','StringType');
        customFiel1dMap.put('StringValue','Received');
        customFieldList.add(customFiel1dMap);

    //  Adding the Invoice Custom Fields
    invoiceMap.put('CustomField',customFieldList);

    invoiceMap.put('Address',new Map<String, Object>{'FreeFormNumber' => '+919090909090'});
    invoiceMap.put('SalesTermRef',new Map<String, Object>{'value' => '4'});
    invoiceMap.put('CustomerRef',new Map<String, Object>{'value' => '29'});

    //  Initializing the Billing Address
    Map<String, Object> billAddrMap = new Map<String, Object>();
        billAddrMap.put('City' , 'Suryapet');
        billAddrMap.put('Country' , 'India');
        billAddrMap.put('Line3' , 'Kodad');
        billAddrMap.put('Line2' , 'First Lane');
        billAddrMap.put('Line1' , '1-24');
        billAddrMap.put('PostalCode' , '508238');
        billAddrMap.put('CountrySubDivisionCode' , '');
    invoiceMap.put('BillAddr',billAddrMap);

    //  Initializing the Invoice Line Items
    List<Object> lineItemList = new List<Object>();
        Map<String, Object> lineItemMap = new Map<String, Object>(); 
        lineItemMap.put('LineNum',1);
        lineItemMap.put('Amount',100);
        lineItemMap.put('Description','Description');
		lineItemMap.put('DetailType', 'SalesItemLineDetail');

        Map<String, Object> salesLineItemDetailMap = new Map<String, Object>();
            salesLineItemDetailMap.put('ItemRef' , new Map<String, Object>{'value' => '1'});
			salesLineItemDetailMap.put('TaxCodeRef' , new Map<String, Object>{'value' => 'TAX'});
            salesLineItemDetailMap.put('ClassRef' , new Map<String, Object>{'value' => '5000000000000193289'});
            salesLineItemDetailMap.put('ServiceDate','1993/05/25'); //yyyy/MM/dd
            salesLineItemDetailMap.put('Qty',2);
            salesLineItemDetailMap.put('UnitPrice',50);
            salesLineItemDetailMap.put('TaxInclusiveAmt',22);
        
        lineItemMap.put('SalesItemLineDetail', salesLineItemDetailMap);
        lineItemList.add(lineItemMap);

        // Shipping charge is applied as a part of line items
        Map<String, Object> shippingLineItemMap = new Map<String, Object>(); 
        shippingLineItemMap.put('Amount',10);
		shippingLineItemMap.put('DetailType', 'SalesItemLineDetail');

        Map<String, Object> shippingSalesLineItemDetailMap = new Map<String, Object>();
            shippingSalesLineItemDetailMap.put('ItemRef' , new Map<String, Object>{'value' => 'SHIPPING_ITEM_ID'});
			shippingSalesLineItemDetailMap.put('TaxCodeRef' , new Map<String, Object>{'value' => 'TAX'});
        
        shippingLineItemMap.put('SalesItemLineDetail', shippingSalesLineItemDetailMap);
        lineItemList.add(shippingLineItemMap);

    //  Adding the Line Items to Invoice
    invoiceMap.put('Line',lineItemList);
    invoiceList.add(invoiceMap);

//  Initializing the RequestJSON Data to be passed.
    Map<String, Object> reqJSONMap = new Map<String, Object>(); 
    reqJSONMap.put('invoices' , invoiceList); 
    String reqJSON = JSON.serialize(reqJSONMap); 

    Map<String, Object> finalReqMap = new Map<String, Object>(); 
    Map<String, Object> reqOptions = new Map<String, Object>(); 
    finalReqMap.put('options' , reqOptions); 
    finalReqMap.put('version' , '1.0'); 
    finalReqMap.put('action' , 'createinvoice'); 
    finalReqMap.put('RequestJSON' , reqJSON); 
    finalReqMap.put('skipDML' , false);
    //Required, if QuickBooks Multi-Org is enabled in Breadwinner. 
    finalReqMap.put('qbOrgId', '!aa00TM'); 
    System.debug('Request ::: ' + finalReqMap);

//  Placing a request to Breadwinner Global API
    Map<String, Object> respMap = breadwinner_qbo.BreadwinnerQBAPI.call(finalReqMap);
    System.debug('Response ::: ' + respMap);