This code snippet used to create a website using PnP Core Component - CSOM Extensions

PnP.createweb.cs

//Author: Shantha Kumar T
// Assembly Reference Used: OfficeDevPnP.Core, Version=2.4.1605.0, Culture=neutral, PublicKeyToken=3751622786b357c2
//Supports: SharePoint Online, SharePoint 2013+

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Microsoft.SharePoint.Client;
using OfficeDevPnP.Core;

namespace SampleApplication
{
    class Program
    {
        static void Main(string[] args)
        {
            string siteUrl = "https://sharepointonline.sharepoint.com";   
         bool isInheritPermissions = false;
            bool isInheritNavigation = false;        
 
            AuthenticationManager authManager = new AuthenticationManager();
            //Interactive Login to SharePoint site - Opens a Online signin page to authenticate the user
            var context = authManager.GetWebLoginClientContext(siteUrl);            
 
            Web web = context.Site.RootWeb.CreateWeb(
                        new OfficeDevPnP.Core.Entities.SiteEntity()
                        {
                            Title = "Sample Site",
                            Url = "samplesite",
                            Description = "Site creating for testing purpose",
                            Template = "STS#0",
                            Lcid = 1033
                        }, isInheritPermissions, isInheritNavigation);
            Console.WriteLine(web.Title + " site created successfully!");
 
            Console.WriteLine("Press any key to exit.");
            Console.ReadKey();
        }        
    }
}
//OUTPUT:
//Sample Site site created sucessfully!
//Press any key to exit.