If your carrier supports Voice over LTE (VoLTE), you'll see these options:
- Off: Turns off LTE
- Voice & Data: Allows voice calls and cellular-data use over LTE
- Data Only: Allows cellular-data use, but not voice calls over LTE

If your carrier doesn't support VoLTE and is a GSM carrier, you'll see one of these options:
- LTE or 4G: Allows cellular-data use over the LTE or 4G network when available.
- 3G: Allows cellular-data use over the 3G network when available.
- 2G: Allows cellular-data use over the 2G network when available.

Depending on the wireless carrier, 4G can indicate either a UMTS or LTE connection. If your carrier doesn't yet support VoLTE and is a CDMA carrier, you'll see Enable LTE. This allows cellular-data use over the LTE network when available.
Learn more about cellular data networks.