Minecraft wiki entry for Dispenser, associated text: By default, the GUI of a dispenser is labeled "Dispenser". A dispenser's GUI label can be changed by naming the dispenser in an anvil before placing it, or by using the data command‌[Java Edition only]. For example, to label a dispenser at (0,64,0) "My Dispenser", use data merge block 0 64 0 {CustomName:'"My Dispenser"'}.