When you install Live Assist for Dynamics 365, you will need to provide an email address. When the provisioning process is complete, you will receive a notification at this address.
During the install, you will notice that it is possible to install a package for the Dynamics web interface, and also for the Unified Service Desk (USD). If you choose installing for USD, you will notice that the installation guide provides two possible options to do this. Depending on the option you choose, you may receive more than one provisioning email.
Any future provisioning emails (such as if you install the USD package after the web one) will go to the same address you provided initially.
Note: The provisioning notification email should normally arrive within an hour of your installation. However, sometimes it takes longer.