Hi Ajithkumar,
in general it is important to understand that the S4HANA uses the same codeline as Hybris Marketing onPrem. S4HANA Cloud Marketing Edition has a predefined standard customizing and standard segmentation profiles so it is a subset of the almost infinite flexibility you have in an onPremise or private cloud deployment.
Here you get a good overview on both deployment options.
In both deployments we do not offer sales order creation/change but of course you can receive orders from external systems.
Cheers
Jan