Hi Marouane, 

Cloud computing generally means hosting your IT trough a third parties (usually hyperscaler) associated with some services and specific softwares. The payment mode can be Pay as you go or a subscription model during 3 or 5 years.Most of the time, you will discover that you will have to pay more to what you initially planed.

The main benefit of this hosting services is that you are not maintaining IT infrastructure and it works on OPEX model. It is easer to scale.

However if you really want to take the benefits of Cloud computing, you need to adopt some rules such as a turning off your VM when you don't use it, optimize your cloud architecture and apply some rules to your end-users.

Hope my answer helped you to have a better understanding about this topic.

Thanks Antoine for your answer!

Another explanation for you, imagine you need a powerful computer to run a resource-intensive application or store a large amount of data. Instead of purchasing and maintaining your own physical server, you can utilize cloud computing. You connect to a cloud service provider, like Amazon Web Services (AWS) or Microsoft Azure, through the internet. 

The cloud service provider has a vast network of servers and data centers. When you request computing resources or storage, the provider allocates the necessary capacity from their infrastructure. This could include virtual machines, storage space, databases, or software applications.

Your data and applications are securely stored and managed within the provider's data centers. You can access and use them from anywhere with an internet connection, using various devices like laptops, smartphones, or tablets.

In summary, cloud computing is a way to access and use computing resources over the internet, providing convenience, scalability, and cost savings compared to traditional on-premises infrastructure.