[nmarinov]

I usually say "Hey Siri, what song am I listening to?" but it works with a bunch of variations e.g.: "what song is this?"

There's also a bunch of other options to trigger Shazam, main way I use it is from the Control Center: https://support.apple.com/en-us/HT210331

[bobthepanda]

If you have an Apple Watch, you can also set it as a home screen button, which is a lot more discreet in public.