<apex:page action="{!attachOfferPDF}"
       standardController="Quote__c"
       extensions="QuotePDFController"
       readOnly="true"      
       applyHtmlTag="false"     
       sidebar="false"     
       showHeader="false"     
       cache="true"     
       renderAs="pdf">

public with sharing class QuotePDFController {
public PageReference rtn;
public static string recursion = 'false' ;
public string parId;
public quote__c quotesRecords {get;set;}
public Quote_header__mdt quotesHeaders {get;set;}

public QuotePDFController(ApexPages.StandardController standardController){
    quotesRecords = new Quote__c();
    parId = standardController.getId();
        system.debug('parid '+parId);
    quotesRecords = [select Id,Name, (SELECT Id,    Product_Name__c,DifficultyLevel__c,Product__r.Name,Level_Course__c,Onetime_Fee__c,OS__c,Vlab_Configuration__c,PerHourCost__c,PerChallengeEvaluationFee__c FROM Quote_Line_Items__r) FROM Quote__c where Id = 'a071y0000015mwEAAQ' limit 1];
    
    
}
public void attachOfferPDF() {
    
    
    if ( recursion == 'false'){
        recursion = 'true';
        system.debug(recursion);
        PageReference pdfPage = Page.QuoteGeneration;
        Blob pdfBlob = pdfPage.getContentAsPDF();
        Attachment a = new Attachment(parentId = 'a071y0000015mwEAAQ', name='Rahul' + '.pdf', body = pdfBlob);
        insert a;
        system.debug('id is '+a.id);
    }}
}