To use this feature in your WooCommerce site, first Go to admin panel > Appearance > Customise > WooCommerce > Product single and mark “yes” up sells product heading and you can also add require one-line description to it. To know more, see below image.
To related product feature, first Go to admin panel > Appearance > Customise > WooCommerce > Product single and click “on” related product like below image.
