expanded-singles.php file under your
/config directory with the following options available to you. You can also use multi-environment options to change these per environment.
<?php return [ 'expandSingles' => true, 'redirectToEntry' => false, ];
expandSingles- Expands the Singles link on the Entries page to list them like Channels and Structures.
redirectToEntry- Automatically redirects to edit the Single Entry when clicking on the item in the sidebar.
You can also manage configuration settings through the Control Panel by visiting Settings → Expanded Singles.
Available for Craft 2 & Craft 3, unlimited use, free forever.