Order by expiry date

Try using query_posts

'orderby' => 'meta_value',
'meta_key' => '_expiration-date',

Thank you where is best to place the code?

It would depend on how you want to implement this in your theme. There’s some good information in the codex:

https://codex.www.ads-software.com/Function_Reference/query_posts

Thank you its basically working with woo commerce products but manipulated for a training course company using https://codecanyon.net/item/grid-fx-responsive-grid-plugin-for-wordpress/5615317 also! The courses expire after a certain date. So i need them to be ordered by the expiry date.