A latch can store the state of the inputs into its memory which can be sent to the outputs when the enable pin is activated. This is very useful when you are dealing with parallel data and you have multiple devices connected to a bus. This can prevent multiple devices talking at the same time and causing conflicts.
This is an 8-bit latch so it has 8x inputs, 8x outputs with latch and enable pins.
The latch pin records the data on the inputs into the memory, the enable pin outputs the memory on the output pins.
The outputs can also be tri-state which means they can be high, low, or high-impedance. The high-impedance output prevents any current passing in or out of the device. Again, useful when its connected to a parallel bus.
The data sheet for this device is available here: