METHOD ONE: Download and Use a Plugin
You can use one of the recommended plugins listed below, or you can search the WordPress.Org Plugin Directory to find a plugin that you like and meets your needs.
If you choose to search the directory, research any potential plugins thoroughly. Check the ratings, reviews, FAQs, screenshots, and support. Take note of the date the plugin was last updated, the compatible WordPress versions, and if the developer has a website or other means of contacting them with questions besides the support link on the WordPress Plugin directory page.
You can also search for, download, and install plugins through the Plugin > Add New menu option in your WordPress Admin Dashboard.
Child Theme Configurator
Child Theme Configurator is a fast and easy to use CSS editor that allows you to create a child theme and customize it beyond the options of the Customizer. Designed for WordPress users who want to be able to customize stylesheets directly, the Child Theme Configurator lets you easily identify and override the exact CSS attributes you want to customize. It properly enqueues theme and font stylesheets for optimum performance and handles vendor-specific syntax, giving you unlimited control over your WordPress look and feel while leaving your Parent Theme untouched.
Download Child Theme Configurator.
Childify Me allows you to create child themes from any non-child theme directly from the Theme Customizer panel. It also works when previewing a theme before activation and is multi-site compatible.
Download Childify Me.
One-Click Child Theme
One-Click Child Theme adds a Theme option to any active theme allowing you to make a child theme. This plugin is useful for shared hosting, especially one-click WordPress installs, which usually involve learning how to use FTP and shell accounts, as it allows you to easily create child themes from any theme just by clicking.
Download One-Click Child Theme.