How to Setup Meta Description while creating Post using WordPress Rest API

Hello,

Thank you for reaching out to us and bringing your concern to our attention.

You need to pass a property data with the meta name called rank_math_description along with your title, content, status, and so on.

Here’s an example of how to do that:

$post_data = array(
	'title'   => 'Your programmatically added post',
	'status'  => 'draft',
	'rank_math_description' => 'Your Rank Math meta description'
);

$request_args = array(
	'headers' => array(
			'Authorization' => 'Basic ' . base64_encode( "admin:admin" )
	),
	'body' => $post_data
);

wp_remote_post(
	'http://DOMAIN.COM/wp-json/wp/v2/posts',
	$request_args
);

Hope that helps and please do not hesitate to let us know if you need my assistance with anything else.