You can use the ‘Ok Google’ hot word on your Android smartphone and tablet or on your PC using the Chrome browser. Did you know that Google stores all those recordings of your voice on its servers for use in making its algorithms smarter at identifying you among other things? Sadly there isn’t much you can do about that. But you can stop Google from associating any of those recordings with you. So nothing ever comes back to you, or so we are made to believe.
You can find a record of all recordings of yourself ordering your device around here https://history.google.com/history/audio
You can actually make your voice unidentifiable by disassociating yourself with it by turning off the “Your voice searches and commands” option here https://www.google.com/settings/accounthistory/audio?continue=https://history.google.com/history/audio