We just bought an inexpensive, low-end Android Tablet (the Insignia Flex 8") running Android 6.0. The navigation bar buttons (which are also called, apparently, the "Home Touch buttons", "On-Screen Virtual Buttons", are the default set of three: Back, Home and Overview buttons (the same set shown in What is the offical name of the third on-screen button?).
Now, my LG K7 phone (running 5.1.1) also came with the same default set of buttons, but they are customizable: by going to Settings > Display > Home touch buttons > Button combination I can choose up to 5 buttons to include in that row. I can't figure out, though, if there is a comparable setting in the Insignia Flex. Is there a way to customize those buttons?
The device, by the way, is not rooted, and I prefer to keep it that way. I am looking for a way to do this using only the built-in features of the device.