Azure provides a complete enterprise-grade 3-tier web application architecture combining presentation tier (App Service/Static Web Apps), application tier (App Service/Container Instances), and data tier (SQL Database/Cosmos DB) with separate scaling, security groups, and subnet configurations within virtual networks. The architecture separates concerns enabling independent optimization of each layer, implements stateless application design patterns for horizontal scaling, uses managed services to eliminate operational overhead, and integrates comprehensive security at every layer including VNet isolation, NSGs, WAF, encryption, and Azure AD authentication.