A HDMI Splitter will split the signal from a single source device to facilitate simultaneous connection to multiple displays. HDMI splitters can send a single video signal to two HDMI monitors at the same time.
How do I split my laptop HDMI between two monitors?
HDMI Splitter This lets you expand your single HDMI port to two external displays. No power input is required. Just plug the single USB end into your computer’s HDMI port, and plug each of your two monitors into each of the two HDMI ports at the other end of the adapter.
Can I use an HDMI splitter to extend not duplicate my laptop screen across two monitors?
An HDMI splitter can’t extend the display to two monitors. What a splitter does is mirror the original image to 2 or more displays. A USB-to-HDMI adapter may effectively add a second HDMI port, which will extend the display. However, not all computers are able to output to a display via a USB port.