Creating the child theme is an easy process. You can create and activate the child theme in two different ways.

First method:

You can create and activate the child theme manually. To create the child theme manually please follow below given steps:

Step 1: Go to your /wp-content/themes/ and create a folder for your new child theme. You may name it anything you’d like. For example, If you want to create the child theme of Travel Log, name it as travel-log-child.

Step 2: Create a stylesheet file within the child theme folder. This must be named style.css. Copy and paste the following code into the file you’ve just created:

/**
* Theme Name: Travel Log Child
* Author: WEN Solutions
* Template: travel-log
* Text Domain: travel-log-child
* Description: Travel Log is a simple and clean Travel WordPress Theme.
*/

The two necessary items in the code above are the lines starting with “Theme Name" and “Template.”  The theme name tells WordPress what the name of your theme is, and the template tells WordPress which theme it should consider as the parent theme.

Step 3: Finally,  you have to make sure to enqueue the parent and child style through the functions.php file of the child theme.

Code to enqueue  style of parent and child theme is given below:

<?php
/**
 *Recommended way to include parent theme styles.
 *(Please see http://codex.wordpress.org/Child_Themes#How_to_Create_a_Child_Theme)
 */  
  add_action( 'wp_enqueue_scripts', 'travel_log_child_style' );
  function travel_log_child_style() {
	wp_enqueue_style( 'parent-style', get_template_directory_uri() . '/style.css' );
	wp_enqueue_style( 'child-style',get_stylesheet_directory_uri() . '/style.css',array('parent-style'));
}

Second method : 

Since the first method is little bit time consuming, you can directly activate the child the using the plugin give below:

https://wordpress.org/plugins/wp-child-theme-generator/