The availability of USB-C ports as the exclusive kind in 12-inch MacBook and 2016 MacBook Pro series clearly indicates that one needs adaptor to connect with any present device with it. Well, good news is that these can be availed in great variety through reputed retail stores like Amazon for getting connected with printers, storage devices, monitors, etc.
Connecting a display with the MacBook
You can have video signal without replacing the present external mirror through the USB-C and Thunderbolt 3 ports on MacBook. All that you need is an adaptor to meet the input of your display.
An old projector can be connected through a VGA output. USB-C VGA MultiPort Adaptor by Apple can be a nice recommendation on this regard, and it also constitutes a USB-C power port, which considered essential for the single-port 12-inch MacBook. The port costs £49/US$49/AUS$75.
There is also a USB-A port available for connecting with an additional device or a hub with extra ports, with adequate 5Gbps bandwidth share stuffs within the connected devices. All that you need to ensure is that your hub supports USB 3.0.
There is also the option available as USB-C adaptor with one exclusive HDMI output. This can also do the job on a MacBook Pro having numerous ports. However, interesting fact here is to mention that one can have models with extra ports at a little extra expense. This can be a very good idea for maintaining flexibility in expansion capacity. Digital A.V MultiPort Adapter comes with a USB-C power port and one USB-A, exactly as its VGA model. The Apple MultiPort Adapter costs £49/US$49/AUS$75.
It holds capacity to run a 4k display. However, it assures to the HDMI 1.4b specs, which means you can expect only 30Hz refresh rate with it, which is still quite good for most of the consumer videos. But, a user might find teetered motion even with little movement of a printer. Well, you can enjoy greater experience if your monitor has DisplayPort, and it supports 4K at 60 Hz.