Fatal Error Called Undefined function

How did you create your child theme for Twenty Sixteen?

By the method of most common one.

I used to put some codes into functions.php for creating child theme.

Where the error comes from? Could you know of it?

By the method of most common one.

No, I don’t think so. ??

A child theme has 2 files at a minimum. A style.css file and a functions.php file. Nothing else. That’s documented here.

https://codex.www.ads-software.com/Child_Themes

You’re getting errors on wp-content/themes/twentysixteen-child/comments.php and that file should not even exist.

Did you copy files from the parent directory into the child directory? If so which ones and why?

I copied all of the files from parent directory to child because I want to edit all of them.

comments.php deleted on child folder but the error still continues…

Okay deleted the navigation code and it has fixed . thanks..

RESOLVED BY ME.

I copied all of the files from parent directory to child because I want to edit all of them.

That’s not a child theme.

Start with the basics.

Backup that whole /twentysixteen-child/ directory and then once you’ve done that and have that backup then delete all those files.

I’m not kidding about the backup.

Then in the now empty /twentysixteen-child/ directory create this one file.

style.css

In that file put the following lines, nothing else.

/*
Theme Name: Twenty Sixteen Child Theme
Version: 0.1
Template: twentysixteen
*/

Now create a functions.php file and copy these lines into it.

<?php

add_action( 'wp_enqueue_scripts', 'mh_twentysixteen_child_style' , 5 );

function mh_twentysixteen_child_style() {
        wp_enqueue_style( 'twentysixteen-parent-style', get_template_directory_uri() . '/style.css' );
}

That’s all, just those 2 files with those few lines. Now activate the Twenty Sixteen Child Theme in your WordPress dashboard.

This way when you look at the wp-content/themes/twentysixteen-child directory all you will see is these 2 files.

style.css
functions.php

Once that’s done: what you you want to change?

EDIT: OK, I’m glad you sorted it out. ??

Okay i will do your suggestion too.

Deleting non-edited files from the current child theme…

Because I added much more ads code into some files on child theme so I dont wanna lose them all.