Re: Cellular setting on 6s
If you've added the free Verizon Advanced Calling feature to your account, you can use "voice and data" to do VoLTE calls, which will also allow you to do simultaneous voice and data while on mobile data. However, there are a few things to know. First, as it exists now, any calls received on LTE will be dropped if you lose LTE coverage and enter a CDMA-only coverage area; VoLTE calls cannot roam to CDMA. Second, any calls made when you are not in an LTE coverage area will not have simultaneous voice and data, and, like VoLTE calls, they cannot roam to VoLTE when you enter LTE coverage - they stay on CDMA.
These days there are few places where there is Verizon coverage without LTE, but it does happen, particularly in rural areas.
VoLTE calls are also what Verizon calls "HD voice" - the voice quality is much higher when the signal is good.
So, to summarize, if you need simultaneous voice and data, if you live in an area with good LTE coverage, turn on Advanced Calling on your account and then you can use "voice and data" for LTE. If you don't really care about simultaneous voice and data, you may be able to live without it.