Microsoft Entra Conditional Access (CA) evaluates signals from the user, device, location, and risk to make access decisions. The platform explicitly notes that CA decisions occur after primary sign-in: “Conditional Access policies are enforced after the first-factor authentication has been completed.” This means a user must successfully present their initial credentials (e.g., password, Windows Hello, FIDO2) before the CA engine evaluates policy logic. Therefore, the statement that CA is evaluated before a user is authenticated is not correct.

Regarding scoping, CA can target ordinary and privileged identities. The assignment options allow administrators to aim policies at users, groups, and directory roles: “You can include or exclude users and groups… [and] include or exclude specific Azure AD directory roles from a Conditional Access policy.” Because Global Administrator is a directory role, policies can be applied to those accounts (with Microsoft’s best-practice guidance to maintain at least one excluded break-glass account to prevent lockout).

For signals/conditions, CA supports device platform filtering. The documented device platform condition states: “This condition is based on the operating system platform of the device… iOS, Android, Windows, macOS (and others).” Administrators commonly use this to require different controls (like MFA or compliant device) based on Android or iOS.

Putting these together:

CA can apply to Global Administrators (Yes).

CA is evaluated after first-factor authentication (No to “before”).

Device platform (e.g., Android/iOS) is a valid CA signal (Yes).