How Do I Set preferred network type to 4G only?

In laymans terms, the difference between 4G and LTE is that 4G is faster than LTE . The reason for this is that 4G meets the technical standards designated for it whereas LTE data transfer speed standard is merely a stopgap measure standard devised until actual 4G speed is realized.

Dialing*#*#4636#*#* or *#36446337#: In both modes you should access Networks and set a Preffered Mode from the menu to LTE only (or whichever mode your prefer at that time).

4G+ is a faster version of 4G. 4G+ is also called LTE-A, LTE-Advanced or 4.5G.

LTE stands for Long Term Evolution. It’s a term used for the particular type of 4G that delivers the fastest mobile Internet experience. You’ll usually see it called 4G LTE. Using a 4G smartphone on Verizon’s 4G LTE network means you can download files from the Internet up to 10 times faster than with 3G.