HI ANUTEJ,

You are correct ! By mistake i have provided a quote id instead of opportunity ID. Because if any record under the Opportunity that's directly don't have a permission to share. Those records basically controlled by parent, Here parent is opportunity. So Obviously we should share the opportunity records as well.

I have changed my code and  trying to share opportunity record but i am facing following Error (In sufficient Access)
 

Error:

12:02:24:180 USER_DEBUG [37]|DEBUG|Exception -System.DmlException: Insert failed. First exception on row 7; first error: INSUFFICIENT_ACCESS_ON_CROSS_REFERENCE_ENTITY, insufficient access rights on cross-reference id: []

Modified Code
 

public class GD_CreateQuoteTeam { 
    @AuraEnabled
    public static void saveQuoteTeam(List<GD_Quote_Team__c> teamList, string quoteId){
        try{
            system.debug('Enter Into the Apex ******' + teamList);
            list<GD_Quote_Team__c> qtTeamList = new list<GD_Quote_Team__c>();
            list<opportunityShare> readShareList = new list<opportunityShare>();
            list<opportunityShare> editShareList = new list<opportunityShare>();    
            
            GD_Quote__c qt = [select id,GD_Opportunity__c from GD_Quote__c where id =: quoteId];
            id oppId = qt.GD_Opportunity__c;
            for(GD_Quote_Team__c team : teamList){
                team.GD_Quotes__c = quoteId;
                qtTeamList.add(team);
            }
            Insert qtTeamList;
            
            for(gd_quote_Team__c qTeam : [select id,name,GD_user__c from gd_quote_Team__c where GD_Quotes__c =: quoteId and GD_Quote_access__c = 'Read Only']){
                opportunityShare shareRecord = new opportunityShare();
                shareRecord.OpportunityAccessLevel = 'Read';
                shareRecord.UserOrGroupId = qTeam.GD_user__c;
                shareRecord.OpportunityId = oppId;
                readShareList.add(shareRecord);
            }
            if(readShareList.size()>0){insert readShareList;system.debug('Read Access Provided');}        
           
            for(gd_quote_Team__c qTeam : [select id,name,GD_user__c from gd_quote_Team__c where GD_Quotes__c =: quoteId and GD_Quote_access__c = 'Read/write']){
                opportunityShare shareRecord = new opportunityShare();
                shareRecord.OpportunityAccessLevel = 'edit';
                shareRecord.UserOrGroupId = qTeam.GD_user__c;
                shareRecord.OpportunityId = quoteId;
                editShareList.add(shareRecord);
            }
            if(editShareList.size()>0){insert editShareList;system.debug('Edit Access Provided');} 
        }catch(Exception e){system.debug('Exception -' + e);}
        
    }
    
}

Many Thanks for your support.
Soundar Rajan P.