Creating a child theme in WordPress is a fantastic way to customize your site without directly modifying the parent theme’s files. This approach ensures that your modifications remain even when the parent theme receives updates. This comprehensive guide will provide you with a step-by-step guide to help you get started:

Step 1: Create a New Folder for the Child Theme

Access Method: Access WordPress installation via FTP or hosting file manager.
Directory Navigation: Navigate to wp-content/themes/ directory.
Child Theme Creation: Create a new folder for the child theme, naming it with the parent theme name and “child” (parenttheme-child) suffix.

Step 2: Create a style.css File

File Creation: Create a file named style.css inside the child theme folder.
Code Addition: Add the provided code to the style.css file.

/*
Theme Name:   Parent Theme
Child Theme URI:    http://example.com/parent-theme-child
Description:  A child theme of Parent Theme
Author:       Your Name
Author URI:   http://example.com
Template:     parenttheme
Version:      1.0.0 */
 
/* Add your custom CSS below this line */

Step 3: Create a functions.php File

File Creation: Create a file named functions.php in the child theme folder.
Code Addition: Add code to enqueue the parent and child theme styles.

<?php
function child_theme_enqueue_styles() {
    // Enqueue parent theme styles
    wp_enqueue_style('parent-style', get_template_directory_uri() . '/style.css');
    // Enqueue child theme styles
    wp_enqueue_style('child-style', get_stylesheet_directory_uri() . '/style.css', array('parent-style'));
}

add_action('wp_enqueue_scripts', 'child_theme_enqueue_styles');

*This ensures that the parent theme’s styles are loaded before the child theme’s styles.

Step 4: Activate the Child Theme

Access WordPress Dashboard: Log in to your WordPress dashboard.
Locate Child Theme: Go to Appearance > Themes.
Activate Child Theme: Click Activate on the child theme listing.

Step 5: Customize Your Child Theme

Custom Template Addition: Copy the template file (e.g., page.php, single.php) from the parent theme folder into the child theme folder and modify it to override templates from the parent theme.
Custom CSS Addition: Add additional CSS to the style.css file.
Custom Function Addition: Add custom functions to the functions.php file.

Optional: Add a Screenshot

File Creation: Create a screenshot.png file with dimensions 1200×900 pixels.
File Location: Place the file in the child theme folder.
File Display: The image will be displayed in the WordPress admin under Appearance > Themes.

Example Folder Structure

wp-content/themes/parenttheme-child/

├── style.css

├── functions.php

└── screenshot.png (optional)

By adhering to these steps, you have successfully created a child theme in WordPress. You can now safely customize your site without losing changes when the parent theme is updated.