Your interview code may be found at the bottom of the interview invitation email. The location of the interview code within the email may vary depending on the company you applied to.
If you are using a mobile device for the interview, you will need to download the HireVue app. (When searching in the App store or Google Play store, it is the one named “HireVue for Candidates”.) Once the HireVue app is downloaded, go back to the invitation email and click the option to start the interview. Your interview code will populate into the HireVue app.