Add a custom section in the content editor

Here the procedure to add a custom section after the Quick Info section in the content editor. Like this:

• Create a new class like this:

  using Sitecore.Shell.Applications.ContentEditor.Pipelines.RenderContentEditor;
  using System;
  using System.Collections.Generic;
  using System.Linq;
  using System.Text;
  using System.Threading.Tasks;
  
  namespace SitecoreTestCustomizeContentEditor
  {
      public class TestSection
      {
          public void Process(RenderContentEditorArgs args)
          {
              args.EditorFormatter.RenderSectionBegin(args.Parent, "CustomInfo", "CustomInfo", "CustomInfo", "Applications/16x16/information.png", true, true);
              args.EditorFormatter.AddLiteralControl(args.Parent, "<div>test value</div>");
              args.EditorFormatter.RenderSectionEnd(args.Parent, true, true);
          }
      }
  }

• Deploy this class in your bin folder
• Add a pipeline into web.config in the renderContentEditor section like this

  <renderContentEditor>
   <processor type="SitecoreTestCustomizeContentEditor.TestSection, SitecoreTestCustomizeContentEditor" />
   <processor type="Sitecore.Shell.Applications.ContentEditor.Pipelines.RenderContentEditor.RenderSkinedContentEditor, Sitecore.Client" />
   <processor type="Sitecore.Shell.Applications.ContentEditor.Pipelines.RenderContentEditor.RenderStandardContentEditor, Sitecore.Client" />  
  </renderContentEditor>