Add schema.org markup generated by Schema plugin to the content https://schema.press/

schema_wp_markup_output_in_content.php

<?php //* do not include php tag

add_filter('the_content','my_schema_wp_markup_output_in_content_6876867');
/**
 * Add schema.org markup generated by Schema plugin to the content 
 *
 * return string
 */
function my_schema_wp_markup_output_in_content_6876867( $content ) {
	
	global $post;
	
	// get markup from post meta
	$schema_json = get_post_meta( $post->ID, '_schema_json', true );
	
	/*
	*	You can do it this way...
	*
		ob_start();
		echo '<script type="application/ld+json">' . json_encode($schema_json, JSON_UNESCAPED_UNICODE) . '</script>';
		$final_script = ob_get_contents();
		ob_end_clean();
	*
	*/
	
	// or simply do it liek this
	$final_script = '<script type="application/ld+json">' . json_encode($schema_json, JSON_UNESCAPED_UNICODE) . '</script>';
	
	// return the content and final script
	return $content . $final_script;
}