I’ve found many support requests, both on WordPress.org support forum and the WooThemes Help Desk, about how to add a customer logout link in the main menu.
Some themes include their own methods to do so, there are also many custom snippets to add in your
functions.php file to add the Logout link manually.
Did you know that WooCommerce has a feature to allow you to easily add the link to the menu? Furthermore, it will be automatically hidden to customers who are not logged in!