Deployments can be protected with Password protection and SSO protection. Password protection is available for Teams on Pro and Enterprise plans, while SSO protection is only available for Teams on the Enterprise plan. Both methods can be used to protect Preview and Production deployments.
Password protection applies to Preview deployments and Production deployments. This feature can be enabled through the Teams Project dashboard. Read more about in the documentation here.
Vercel Authentication protection applies to Preview deployments and Production deployments. When enabled, a person with a Personal Account that is a member of a Team, can use their login credentials to access the deployment. This feature can be enabled through the Teams Project dashboard.
Both Password protection, and Vercel Authentication can be enabled at the same time. When this is the case, the person trying to access the deployment will be presented with an option to use either method to access the deployment.