SF_10.1, SF_10.2, SF_11.0, SF_11.1, SF_11.2, SF_12.0, SF_12.1, SF_12.2, SF_13.0, SF_13.1, SF_13.2, SF_13.3 - https://docs.sitefinity.com/for-developers-create-page-templates

CreatingPageTemplate.cs

using System;
using System.Linq;
using System.Text.RegularExpressions;
using Telerik.Sitefinity;
using Telerik.Sitefinity.Abstractions;
using Telerik.Sitefinity.Model;
using Telerik.Sitefinity.Modules.Pages;
using Telerik.Sitefinity.Pages.Model;

namespace Telerik.Sitefinity.Documentation.CodeSnippets.DevGuide.SitefinityEssentials.PageTemplates
{
    public partial class PageTemplateSnippets
    {
        public static Guid CreatePageTemplate(string templateTitle)
        {
            Guid templateId = Guid.Empty;
            var fluent = App.WorkWith();
            var parentTemplate = fluent.Page().PageManager.GetTemplate(SiteInitializer.TemplateIdRightSidebarHeaderFooter);
            templateId = fluent.PageTemplate()
                               .CreateNew()
                               .Do(t =>
                               {
                                   t.Title = templateTitle;
                                   t.Name = new Lstring(Regex.Replace(templateTitle, @"[^\w\-\!\$\'\(\)\=\@\d_]+", String.Empty).ToLower());
                                   t.Description = templateTitle + " descr";
                                   t.ParentTemplate = parentTemplate;
                                   t.ShowInNavigation = true;
                                   t.Framework = PageTemplateFramework.Hybrid;
                                   t.Category = SiteInitializer.CustomTemplatesCategoryId;
                                   t.Visible = true;
                               })
                               .SaveAndContinue()
                               .Get()
                               .Id;
            var pageManager = PageManager.GetManager();
            var template = pageManager.GetTemplates().Where(t => t.Id == templateId).SingleOrDefault();
            var master = pageManager.TemplatesLifecycle.Edit(template);
            pageManager.TemplatesLifecycle.Publish(master);
            pageManager.SaveChanges();

            return template.Id;
        }
    }
}