I have managed to create a dynamically mapping fields from my custom object to map and pass the field name. I have one problem. I map the address field to Account Billing field. I want to add Phone to be map as Phone__c from my custom object field. The code is as follows:


/*

Account_TriggerHandler

*/

public static void createNewCustomObjectReplicateFromAccount(List<Account> newA){
        
        List<Account> lstRequiredRecordTypefromAccount = new List<Account>();
        Id Required_REC_ID = Schema.SObjectType.Account.getRecordTypeInfosByName().get('TypeName').getRecordTypeId();
        
        List<String> fieldName = customObjService.getFieldName();
        Map<String,String> addressField = customObjService.getMapField();
        
        
        for(Account a : newA){
            if(a.RecordTypeId == Required_REC_ID) lstRequiredRecordTypefromAccount.add(a);
        }
        
        List<customObj__c> customObj2Insert = new List<customObj__c>();
        
        
        for(Account a : lstRequiredRecordTypefromAccount){
            
            customObj__c ss = new customObj__c(Account__c=a.Id);
            
            
            //Capture current date
            ss.custom_Date__c = Date.today();
            
            for(String f : fieldName){
                
                String ssField = (f.startsWith('Billing'))?addressField.get(f):f;
               
                
                //Only update the Account field when there is a value on customObj__c
                if(a.get(f) != null){
                    
                    ss.put(ssField,a.get(f));
    
                   
                    
                }
                
            }
            
            customObj2Insert.add(ss);
        }
        
        insert customObj2Insert;
        
        
    }
}

and from service:

public with sharing class customObjService {
    
    public static final Set<String> FIELD_NOT_MAPPED_TO_ACCOUNT = new Set<String>{'field1__c','field2__c','field3__c','Account__c','Id'};
    
    public static Map<String,String> addressField = getMapField();
    
            
    public static List<String> fieldName = getFieldName();
    

        
    public static List<String> getFieldName(){
        
        List<String> tmp = new List<String>();
        
        Map<String,String> mapField = getMapField();
        
        
        System.debug('>>>mapField: ' + mapField);
        
        Map<String, Schema.SObjectField> customObjMap = Schema.getGlobalDescribe().get('customObj__c'.toLowerCase()).getDescribe().Fields.getMap();
        //Get all field name from customObj__c sObject
        if (customObjMap != null){
            for (Schema.SObjectField ft : customObjMap.values()){
                String f = ft.getDescribe().getName();
                Integer len = f.length() - 3;
                
                if(f.indexOf('__c') == len && !customObjService.FIELD_NOT_MAPPED_TO_ACCOUNT.contains(f)){
                    tmp.add((f.startsWith('Address'))?mapField.get(f):f);
                    
                    system.debug('tmp >>>' + tmp);
                }
                
            }
        }
        //system.debug('tmp >>>' + tmp);
        return tmp;
    }
    
   
    
    public static Map<String,String> getMapField(){
        
        Map<String,String> tmp = new Map<String,String>();
        //From Custom Object to Account
        tmp.put('Address_Street__c','BillingStreet');
        tmp.put('Address_City__c','BillingCity');
        tmp.put('Address_Country__c','BillingCountry');
        tmp.put('Address_State_Province__c','BillingState');
        tmp.put('Address_Zip_Postal_Code__c','BillingPostalCode');
        
        
        
        //From Account to Custom Object
        tmp.put('BillingStreet','Address_Street__c');
        tmp.put('BillingCity','Address_City__c');
        tmp.put('BillingCountry','Address_Country__c');
        tmp.put('BillingState','Address_State_Province__c');
        tmp.put('BillingPostalCode','Address_Zip_Postal_Code__c');
        
        
        return tmp;
    }
}

Please let me know how to include  standard  fields like Phone.

Thanks for your help