Hi Jainam,
I have created the lead conversion.. while converting the lead both contact and acount details are deleting. i want only existing account details to be deleted.
Please check the below code.

Trigger web2LeadConvert on Lead (after Update) {
 LeadStatus convertStatus = [
      select MasterLabel
      from LeadStatus
      where IsConverted = true 
      limit 1
 ];
 List<String> Aname = New List<String>();
 List<Database.LeadConvert> leadConverts = new List<Database.LeadConvert>();
 
map<string,string> statemap = new map<string,string>();
for (State_Code__mdt StateNames : [SELECT State_Name__c, State_Code_Name__c FROM State_Code__mdt]) {
    statemap.put(StateNames.State_Name__c,StateNames.State_Code_Name__c); 
    system.debug('%%%%%%%%>' +Statenames);
    
}

for (Lead lead: Trigger.new) {
   if (!lead.isConverted && lead.Status == 'Closed - Converted') { 
        if (statemap.containsKey(lead.State)) {
            Aname.add(lead.Company+' '+lead.City+' '+statemap.get(lead.State));
            system.debug('#####' + Aname);
        }

            Database.LeadConvert lc = new Database.LeadConvert();
            
           lc.setLeadId(lead.Id);
          
           lc.setConvertedStatus(convertStatus.MasterLabel);
           
           lc.setDoNotCreateOpportunity(TRUE);
           
           leadConverts.add(lc);

           system.debug('LeadConverts @@@@@'+leadConverts);
        }
      }
 
 if (!leadConverts.isEmpty()) {
      
     List<Database.LeadConvertResult> lcr = Database.convertLead(leadConverts); 
     
     System.debug('--------->' +lcr);
     List<ID> ConvertedAccount = New List<ID>();
      For(Database.LeadConvertResult lr : lcr){
         
         ConvertedAccount.add(lr.AccountId);
      }  
     
      List<Contact> contacs = [Select ID,Accountid,Account.Name,LastName From Contact Where Accountid IN : ConvertedAccount];
      
      system.debug('******' + contacs);
     /*Map<String , Contact> AllContacts = New Map<String , Contact>(); 
     For(Contact c : contacs){
         AllContacts.put(c.Account.Name, c);
          system.debug('&&&&&&&&' + Allcontacts);
     } */
     List<Contact> cc = New List<Contact>();
     List<Account> acc = [Select id, Name, (Select ID, Lastname From Contacts) From Account Where Name IN : Aname Order by CreatedDate DESC];
      
      system.debug('List of acc$$$$$' + acc);
      
     /*For(Account a : acc){             
         If(AllContacts.get(a.Name) != Null && AllContacts.get(a.Name).Name!= a.Name){                
             Contact c = AllContacts.get(a.Name);
             c.Accountid = a.id;                 
             cc.add(c);
         }
     }
     update cc;*/
     If(acc.size() != 0){ 
     for(contact con  : contacs){
         con.accountId = acc[0].Id;
         cc.add(con);
     } 
     update cc;
     List<Account> DeleteAccount = [Select Id From Account Where Id IN : ConvertedAccount];
        Delete DeleteAccount;
     }
 
 }
}

Regards,
Sarma