Single sign-on is an option that can be enabled in %BRAND_AAD_CONNECT_SHORT% with either Password synchronization or Pass-through ...

Single sign-on is an option that can be enabled in %BRAND_AAD_CONNECT_SHORT% with either Password synchronization or Pass-through authentication. When enabled, users only need type their username and do not need not to type their password to sign in to %BRAND_AZURE_ACTIVE_DIRECTORY% or other cloud services when they are on their corporate machines and connected on the corporate network. By providing your end users with SSO, access to cloud-based services is more familiar and provides the organization with a secure and simple process that doesn't require any additional on-premises components. For more information, see What is Single Sign On (SSO) (preview).