What is Azure AD Conditional Access?

Azure AD Conditional Access helps you manage your company resources and how they might be accessed. These policies help you maintain control over your Office 365 environment. For example, you can define a conditional access policy that evaluates sign-in connections from mobile devices to Exchange Online, and requires employees use Outlook for iOS or Android to successfully access their work email and calendar. 

To learn more about Conditional access check out this support site: Conditional Access is now part of Microsoft 365 Business! – Microsoft Tech Community