It is virtualization on the internet to store, process and manage data instead of facing the hurdle of buying a physical computer or on a large scale, say a datacenter. There are three types of Cloud Computing services:
IaaS: Leverages businesses to get various components of web architecture like servers, storage, resources like CPU, memory, etc diminishing the need for investing any upfront amount to buy this internet infrastructure.
PaaS: It leverages developers with the platform of their preferred language IDE to build their code to make the final-software and collaborate with other developers without worrying about the need to actually buying the infrastructure.
SaaS: For an end-user, the final software or a website is a software-as-a-service, which they use it without any interest in knowing the language it is made up of. This software is already installed in the cloud server which can be quickly deployed.
To learn AWS at a top-notch level, here is a video below:
Intellipaat's AWS Certification will master you in AWS Cloud and others. Also, you will work on various tools of the AWS cloud platform.