HDMI splitters (and graphics cards) can send video output to two HDMI monitors at the same time.

Can you use a splitter for dual monitors?

Many computers have dual ports and some monitors will work off USB connections. The VGA splitter is one of the more efficient ways of creating a dual monitor connector. The cord is specifically designed to bridge the gap between two monitors while only taking a single port on your computer.

How do I extend my Display to two monitors?

Right-click anywhere on the desktop and select Screen resolution, then choose Extend these displays from the Multiple displays drop-down menu, and click OK or Apply.