Here’s a simple and functional plugin for Moodle, a new user registration Welcome Email generator. The addon was created by Bas Brands and “this plugin sends one email message to users that are new in Moodle and one email to a moderator.”
It purportedly works with all standard Moodle authentication systems and allows various customization options to craft your welcome emails, include user fields and hone how students receive their welcome messages. It could be a really great way to touch base with new users immediately and provide them with any additional post registration instructions for your site.
Download the addon here: https://moodle.org/plugins/view.php?plugin=local_welcome