Create

//  Create a Map to store all the data of a Customer
Map<String, Object> customerMap = new Map<String, Object>(); 
    customerMap.put('CompanyName','Breadwinner Inc');
    customerMap.put('DisplayName','Breadwinner Inc');
    customerMap.put('PrimaryPhone' , new Map<String, Object>{'FreeFormNumber' => '9988543562'});
    customerMap.put('Active',true);
        
    Map<String, Object> billingAddrFieldMap = new Map<String, Object>();
        billingAddrFieldMap.put('City' , 'Suryapet');
        billingAddrFieldMap.put('Country' , 'India');
        billingAddrFieldMap.put('Line3' , 'Kodad');
        billingAddrFieldMap.put('Line2' , 'First Lane');
        billingAddrFieldMap.put('Line1' , '1-24');
        billingAddrFieldMap.put('PostalCode' , '508238');
        billingAddrFieldMap.put('CountrySubDivisionCode' , '');
        
    customerMap.put('BillAddr' , billingAddrFieldMap);
        
    Map<String, Object> shippingAddrFieldMap = new Map<String, Object>();
        shippingAddrFieldMap.put('City' , 'Hyderabad');
        shippingAddrFieldMap.put('Country' , 'India');
        shippingAddrFieldMap.put('Line3' , '');
        shippingAddrFieldMap.put('Line2' , 'Srinagar Colony');
        shippingAddrFieldMap.put('Line1' , '1/78-24');
        shippingAddrFieldMap.put('PostalCode' , '500008');
        shippingAddrFieldMap.put('CountrySubDivisionCode' , '');
        
    customerMap.put('ShipAddr' , shippingAddrFieldMap);

//  Initializing the RequestJSON Data to be passed.
Map<String, Object> requestJSONMap = new Map<String, Object>();
    requestJSONMap.put('customers', new List<Object>{customerMap});
    String reqJSON = JSON.serialize(requestJSONMap);

Map<String, Object> reqObj = new Map<String, Object>();
    reqObj.put('version', '1.0');
    reqObj.put('action', 'createCustomer');
    reqObj.put('requestJSON', reqJSON);
    //Required, if QuickBooks Multi-Org is enabled in Breadwinner. 
    reqObj.put('qbOrgId', '!aa00TM');

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