Transfer Active Call Directly to a Voicemail Box

Question

How can I transfer or forward a call directly to someone's voicemail box? 

Overview

Zoom Phone App: 

1. When on an active call, select the Transfer button
2. Type in the extension of the person you wish to transfer to
3. Select the Transfer button again - Select Transfer to Voicemail 

Yealink Desk Phone: 

1. When on an active call, select the Transfer button 
2. Select Transfer to Voicemail 
3. Enter the extension you wish to transfer to and press Call