Log in with your email/username and password at https://web.voxer.com/.
Please ensure you are on the latest version of Google Chrome, IE or Firefox. They are currently the only supported browsers for Voxer for Web. You will need speakers and microphone to hear and send voice messages.
Once you login, click on the permissions settings on your browser and give Voxer access to your microphone in order to be able to send voice messages.