The plugin has an option to specify a status of WooCommerce orders that will be used as a basis for calculating time of sending review reminders. It is possible to choose a status and specify the number of days that should pass after this order status to trigger sending of review reminders.
Both standard and custom order statuses are supported. If you would like to use a custom order status, make sure that it is classified as 'paid'. The plugin only supports statuses that have 'paid' attribute because it does not make sense to send review invitations for unpaid orders. To determine if an order status is 'paid', the plugin uses the standard WooCommerce function wc_get_is_paid_statuses.