Apple ID offers an option to hide your email address if you use it to authenticate to a third-party application like Shift. This option generates a unique, randomized email address solely for use within that application.
Because Shift creates a unique user profile specific to each email address used to access the service, and does not support multiple email addresses per user, it will treat this app-specific relay email address as a unique user.
Thus, if you use Apple ID to log into Shift and select "Hide my email," Shift will generate a unique reviewer user profile for that email address.
If you would like to access your primary list of workspaces, projects, and Feed, we recommend selecting "Share my email" to log in to that profile.