4G LTE with VVM means Voice over LTE with Visual Voicemail. It's a new way to get your voicemail messages without having to call into your voicemail system. Instead, you can see all of your new messages in one place, and play them back just like you would any other type of message. This visual voicemail service is included for free with most 4G LTE plans from carriers like AT&T, Verizon, T-Mobile, and Sprint. So if you're on a 4G LTE plan from one of these carriers, chances are good that you already have access to this feature.
To use visual voicemail, simply open up the Phone app on your iPhone (it's the green icon with a white telephone receiver inside). Then tap on the Voicemail tab at the bottom of the screen. You'll see a list of all your recent voicemails, along with an indicator next to each one letting you know whether or not you've listened to it yet. To listen to a particular message, just tap on it and it will start playing.
If you want to delete a message, just swipe left on it and tap Delete. Or if you need more options for managing your messages, tap on the Edit button in the top-right corner and then choose from the various options that appear.
Overall, visual voicemail is a convenient way to stay on top of your voicemail messages without having to actually call into your voicemail system every time you want to check for new messages. And since it's included for free with most 4G LTE plans, there's no reason not to take advantage of this handy feature!