Google's Voice Assistant is triggered when the user says 'Ok, Google'. After that, the system captures what you are saying and answers your questions, for example, informing the weather forecast, ...

You can bring Google Assistant up by saying “OK Google” or “Hey Google” wake words. But if you’re in a noisy environment, that might not work well. To solve ...

Quick Phrases will let you perform Google Assistant tasks without requiring the “Ok/Hey Google” hotword. You will be able to set alarms, control your music, and more with this in-development feature.