IaaS (Infrastructure-as-a-Service)
These allow you to have a lot of control over how you run them but also require you to be responsible for things like the OS, Antivirus and Load Balancing.

PaaS (Platform-as-a-Service)
You don’t have to worry about the OS or even the server, you can just run your application. You are responsible for some server configuration, like scalling.

SaaS (Software-as-a-Service)
SaaS is the highest abstraction level and allows you to just use the application, you don’t even have to build it. You just configure it.

Paas:

Web Apps
Abstraction of a Web Server (IIS, Tomcat)
Vailable 99.95%
Python, .Net

Mobile Apps
Easily connect to this backend using the SDKs for Azure Mobile Apps.

Logic Apps (integration platform as a service (iPaaS) built on a containerised runtime.)
A Logic App is started by a Trigger. This can be a time (every 15 minutes) or an outside source, like a new message on a queue. The Trigger passes values into the workflow (like the contents of the queue message), that can be used throughout the Logic App. The rest of the flow of the Logic App consists out of calling Connectors, which are APIs to third party services, like Office365
This is sometimes called “serverless” because it means that you can completely focus on your application or logic and not on the underlying infrastructure.

What is Azure Logic App?

Overview for Azure Logic Apps – Azure Logic Apps | Microsoft Docs

About connectors in Azure Logic Apps

Connectors overview for Azure Logic Apps – Azure Logic Apps | Microsoft Docs

Connectors

MySql, Oracle, Sql Server
PowerBI, Yammer, Mail, 100’s more or create a custom connector

List of all Logic Apps connectors | Microsoft Docs

Azure Functions
Use Azure Functions to host small applications, like background jobs or a microservice that only runs for a short period of time.
Just like Logic Apps, Azure Functions are “serverless”, because they scale automatically and you only pay for them when they run. .

Azure Functions Overview | Microsoft Docs

Azure WebJobs
WebJobs are part of App Services and run inside an App Service like a Web App or a Mobile App.
WebJobs work similarly to Azure Functions in that they run small pieces of code that can be triggered by outside sources that don’t require any plumbing code to set up.

They are different from Azure Functions in that you need to scale them manually. You pay for the App Service that hosts your Web Job, which is a monthly fee, regardless if the WebJob runs or not.
Azure Functions can be triggered by configurable timers, like on a schedule (every 15 minutes) or by an external service

Introduction to Azure Data Factory – Azure Data Factory | Microsoft Docs

Azure Data Factory is a managed cloud service that’s built for these complex hybrid extract-transform-load (ETL), extract-load-transform (ELT), and data integration projects.