What is the difference between Azure PaaS, IaaS, and SaaS?

Model Description Example for .NET

IaaS

(Infrastructure)

Provides virtual machines,

networking, storage

Azure VM running Windows + IIS

hosting ASP.NET app

PaaS (Platform) Managed hosting environment

for apps

Azure App Service, Azure Functions

SaaS (Software) Fully managed software

accessible via browser

Office 365, Dynamics 365