Copyright © 2018 by SCITEPRESS - Science and Technology Publications, Lda. All rights reserved. Voice User Interfaces (VUI) are effective and intuitive for many people. The VUI is rapidly becoming suitable for various practical purposes using voice-operated smartphones, or smart speakers like Amazon Echo or Google Home. If VUIs, which may require less cognitive load to use, are available on learning management systems (LMS) like Moodle, they could enhance LMSs' functionality. This study demonstrates examples of existing educational applications for VUIs and chatbot interfaces. Design suggestions for VUIs for several Moodle activities are also described, and a prototype VUI for Moodle quizzes has been developed with the Dialogflow platform.