question

I believe this can be done by holding down the transfer button, selecting blind transfer (unless blind transfer is already your default transfer type) , and then dialing *0 then the users extension and then pressing transfer once again. By doing that it should automatically transfer the call into the users voicemail. 

There is an article link below that walks you through transferring to voicemail if you have other questions. 

https://support.ringcentral.com/s/article/Deskphones-Transfer-Calls?language=en_US

Thank you, Marina. I was able to get on chat and find that info. You are exactly correct. We set up our phones to be "blind" for default transfer. Then on an incoming call press "Transfer" then "*" then "0" then the extension you want to select, then "#". Routes the caller directly to the extension's voicemail.