By default, WordPress strips HTML from category descriptions. This code will prevent that from happening.

The first part prevents HTML from being stripped from term descriptions.

The second part prevents HTML being stripped out when using the term description function.

Add this code to your child theme’s functions.php file or via a plugin that allows custom functions to be added, such as the Dessky Snippets plugin. Please don’t add custom code directly to your parent theme’s functions.php file as this will be overwritten completely when you update the theme.

/**
 * Allow HTML in term (category, tag) descriptions
 */
foreach ( array( 'pre_term_description' ) as $filter ) {
	remove_filter( $filter, 'wp_filter_kses' );
	if ( ! current_user_can( 'unfiltered_html' ) ) {
		add_filter( $filter, 'wp_filter_post_kses' );
	}
}
 
foreach ( array( 'term_description' ) as $filter ) {
	remove_filter( $filter, 'wp_kses_data' );
}