What are two different types of Power Apps authentication?

Azure Active Directory (Azure AD) Authentication:

Single Sign-On (SSO): Users are authenticated against Azure AD, which often acts as the central identity provider in Microsoft 365 environments. This allows users to use their existing organization credentials to access the Power Apps.

Multi-Factor Authentication (MFA): As an extension to Azure AD authentication, MFA provides an additional layer of security. After initially authenticating with a username and password, users are required to verify their identity using a second factor (e.g., a phone or a security token).

Role-Based Access Control (RBAC): Azure AD enables you to assign roles to users, which can be leveraged within Power Apps to show/hide specific features or data based on the user’s role.
Social Identity Providers:

OAuth Providers: Power Apps can be configured to allow authentication via social identity providers such as Google, Facebook, and others by using OAuth 2.0.

Custom Providers: You can even use custom identity providers if your organization has specific requirements that are not met by Azure AD or other OAuth 2.0-based providers.