Cloud computing is all about the delivery of resources like databases, storage and servers etc on the internet. To understand cloud computing, you should know about these models of cloud computing:
PaaS - This is also known as Platform as a Service. This model provides software and hardware resources to quickly build, host and deploy applications. You can consider this source https://medium.com/geekculture/top-5-paas-platforms-to-consider-for-your-web-app-24982670df81 to understand more about PaaS.
FaaS - Function as a Service permits the development teams to build, run and manage application functionalities without taking care of infrastructure. You can read everything about FaaS and serverless functions through this source https://blog.back4app.com/what-are-serverless-functions-in-cloud-computing/#Function_as_a_Service_FaaS. You also don't have to administer infrastructure with this model.
IaaS - Infrastructure as a Service is an exciting cloud computing model where you get all hardware backing without hosting applications in the absence of on-premises infrastructure.
BaaS - With this Backend as a Service model, you can simply build frontends and CSPs will take care of all of the server-side operations. See this source https://digitalcruch.com/baas-backend-as-a-service/ to find everything about BaaS.