From a Home screen, navigate: Phone app > Voicemail (lower-right).
If switching to an iPhone, you could be directed to the automated Voicemail system. If so, follow the voice prompts. If unsuccessful, you can dial *86 to manually set up.
Tap Set Up Now.
If the 'Set Up Now' pop-up doesn't appear, your Voicemail has already been set up. Simply tap Greeting in the upper-left of the Voicemail screen and begin at step 6.
Enter a password then tap Done.
The password must be between 4-6 digits in length.
Re-enter the password then tap Done.
Tap Custom to record a greeting.
To use a Verizon default greeting, tap (check) Default.