Child theme is one the WordPress’s coolest feature. Child theme is useful when you are using some paid theme or a theme from WordPress repository. The main concept of using child theme is that if you want to customize the ready made theme, you create the child theme. Because if you do not , your changes are lost when you update the original theme Or you have to update the theme manually, which is very difficult if you have too much customization.
How to create WordPress child theme?
If you are new in WordPress and don’t know how to create a child theme you can follow this codex article of child themes
How to solve Parent theme missing error?
Often while creating the child theme people get error like can not create child theme , parent theme not found.
If you are having the same error then you have given wrong template name in your child theme’s style.css
/* Theme Name: Twenty Fifteen Child Description: Twenty Fifteen Child Theme Template: twentyfifteen */
Here the twentyfifteen is the folder name of your parent theme. So make sure you have used the same name. It is also case sensitive. So if your parent theme name is “XyZ”
Now your error should be gone and your child theme must be working. Make sure you import parent theme’s css to child theme’s style.css.