To add on to the post above from "@Nybtim", enabling Data + Voice in LTE settings will allow for simultaneous voice and data use, and will bring improved voice quality with it. Just take note that if the phone begins a call on 3G or 1X rather than LTE, you will not have data service on a call until LTE Service returns (when you are both back in range, AND your call is disconnected).
Using LTE for voice can also cause an increase in dropped calls. If you find this is the case and the problem is bothersome, let Verizon know so they can fix that problem, and feel free to set the LTE setting back to Data. I would suggest against turning off LTE all together.