Just connecting the Pi to an HDMI device will not provide any sort of touchscreen facility - HDMI is output only, and the touchscreen data need to get back to the Pi somehow. When connecting a HDMI monitor with touchscreen, usually there is a USB or similar connection as well.
Principal Software Engineer at Raspberry Pi (Trading) Ltd.
Contrary to popular belief, humorous signatures are allowed. Here's an example...
"My grief counseller just died, luckily, he was so good, I didn't care."