Depending on what cellular provider you have and where in the world you are, the process may differ a little bit. Searches can likely be made to find the specific instructions for your specific provider. All in all, however, most of the set-ups are fairly similar and shouldn’t take very long at all. So without further ado, let’s take a look at the ways to set up your voicemail on the iPhone 6S.
16. I (sleep) eight hours every night. 17. Jet engines (make) a lot of noise. 18. Every Saturday my friends and I (go) to the dancing hall. 19. What you're telling me (frighten) me greatly. 20. The news (shock) everybody in the house.

Some networks will provide a special number for you to ring, although with O2 and some others you just have to dial your own mobile phone number and then hit the * key to enter the voicemail system. Again, you’ll need to make sure that you’ve set up a secure PIN for your voicemail to make sure that none of Rupert Murdoch’s minions can hack into your voicemail from the comfort of their desk.
In order to automatically direct a specific caller to your voicemail without your phone ringing, you’ll have to use a different method depending on which phone you’re using.