It is very risk to run an Uber without the HST number. The Canadian Revenue Authority has warned any uber drivers that operating without a legit HST number can attract serious penalties. As much as you can survive without the HST number, it will be just a matter of time before the authorities catch up with you. The process of getting HST number is easy. Go to your driver's tax information and request for one, you will be able to access it in two to three days.