Edit hidden fields in page editor

I want to edit on Sitecore Page Editor some hidden fields like meta fields from head html section. How can I do it? I try with

 <sc:FieldRenderer runat="server" ID="scFieldMeta" FieldName="Meta title" /> 

but this is not working for head html section.

Sitecore doesn't have out of the box this kind of functionality but you need to follow few steps to do it:

1. Create under item

    /sitecore/content/Applications/WebEdit/Edit Frame Buttons 
   

   a folder, you can name it: PageProperties. Under folder you have to create a new Field Editor Button. On field Fields you need to enter name of the fields you want to edit separate by pipeline. Will be something like :

       Meta data|Meta title
   

2. Under item :

   /sitecore/content/Applications/WebEdit/Ribbons/WebEdit/Page Editor
   

   you need to create an item of type:

    /sitecore/templates/System/Ribbon/Chunk
   

   Under new item you have to create new item of type:

    /sitecore/templates/System/Ribbon/Small Button
   

   On the field Click you will have something like

    command:executefieldeditor(path=/sitecore/content/Applications/WebEdit/Edit Frame Buttons/Page Properties/Page Properties)  
   

   where path will point to item created at step one.

3. On this step you need to create a command. Please create on include folder a new file name it : CustomCommands.config or how do you want with extension config.

   It will contains :

    <?xml version="1.0"?>
    <configuration xmlns:patch="http://www.sitecore.net/xmlconfig/">
        <sitecore>
            <commands>
                 <command name="command:executefieldeditor" type="yournamespace.ExecuteFieldEditor,yourAssembly"/>
          </commands>
      </sitecore>
 </configuration>

4. Create your class :

using Sitecore;
using Sitecore.Data;
using Sitecore.Data.Items;
using Sitecore.Diagnostics;
using Sitecore.Shell.Applications.WebEdit;
using Sitecore.Shell.Applications.WebEdit.Commands;
using Sitecore.Text;
using Sitecore.Web.UI.Sheer;
using System;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace YOURNAMESPACENAME
{
    public class ExecuteFieldEditor : FieldEditorCommand
    {
        /// <summary>
        /// The fieldname
        /// </summary>
        private const string Fieldname = "Fields";

        /// <summary>
        /// The header
        /// </summary>
        private const string Header = "Header";

        /// <summary>
        /// The icon
        /// </summary>
        private const string Icon = "Icon";
        /// <summary>
        /// The uriparameter
        /// </summary>
        private const string Uriparameter = "uri";

        /// <summary>
        /// The pathparameter
        /// </summary>
        private const string Pathparameter = "path";

        /// <summary>
        /// The currentitemisnull
        /// </summary>
        private const string Currentitemisnull = "Current item is null";

        /// <summary>
        /// The settingsitemisnull
        /// </summary>
        private const string Settingsitemisnull = "Settings item is null";

        /// <summary>
        /// Gets or sets the current item.
        /// </summary>
        /// <value>
        /// The current item.
        /// </value>
        private Item CurrentItem { get; set; }

        /// <summary>
        /// Gets or sets the settings item.
        /// </summary>
        /// <value>
        /// The settings item.
        /// </value>
        private Item SettingsItem { get; set; }

        /// <summary>
        /// Gets the options.
        /// </summary>
        /// <param name="args">The arguments.</param>
        /// <param name="form">The form.</param>
        /// <returns></returns>
        protected override PageEditFieldEditorOptions GetOptions(ClientPipelineArgs args, NameValueCollection form)
        {
            EnsureContext(args);
            return new PageEditFieldEditorOptions(form, BuildListWithFieldsToShow()) { Title = SettingsItem[Header], Icon = SettingsItem[Icon] };
        }

        /// <summary>
        /// Ensures the context.
        /// </summary>
        /// <param name="args">The arguments.</param>
        private void EnsureContext(ClientPipelineArgs args)
        {
            CurrentItem = Database.GetItem(ItemUri.Parse(args.Parameters[Uriparameter]));
            Assert.IsNotNull(CurrentItem, Currentitemisnull);
            SettingsItem = Client.CoreDatabase.GetItem(args.Parameters[Pathparameter]);
            Assert.IsNotNull(SettingsItem, Settingsitemisnull);
        }

        /// <summary>
        /// Builds the list with fields to show.
        /// </summary>
        /// <returns></returns>
        private IEnumerable<FieldDescriptor> BuildListWithFieldsToShow()
        {
            ListString fieldString = new ListString(SettingsItem[Fieldname]);

            return (from field in new ListString(fieldString) where CurrentItem.Fields[field] != null select new FieldDescriptor(CurrentItem, field)).ToList();
        }
    }
}

Also you can check this post.