monitor
The Monitor displays the user interface and programs, allowing the user to interact with the computer, typically using a mouse and keyboard. Most modern monitors are built using LCD technology and are commonly referred to as flat screen displays.
printer
Printers are an output device that prints paper documents. This includes text documents, images, or a combination of both. The printer output produced is often a hard copy, which the physical version of an electronic document. Most modern printers are connected using a standard USB cable. But some printers can be connected to one or more computers over a Wi-Fi network. A printer can be used on multiple computers as long as the drivers are installed