It’s pretty easy to do with virtual switches. Here’s a thread on it
For me, I use a modified version of what’s in that thread along with virtual momentary switches. I only use the switches to send the commands and so I use the momentary switches (not monitoring the state). The benefit of the momentary switches is that when pressed, they send an on command followed by an off. I use the app to monitor only the on commands and send the HH command.
IFTTT then can send on commands to the virtual switch or monitor for the switch being turned on. Monitoring the on works well. I use it to trigger harmony commands via IFTTT when I push the virtual button.
Here’s my modified code in case you want to use it. In addition to only using the on command, there’s an optional delay, which I use in my case to set the away mode. This way, I can arm the away mode 60 seconds after pressing the button so I can get out the door without an alert.
https://github.com/tierneykev/SmartThings/blob/master/Hello%20Home%20Momentary%20Switch