Optimal Environment

Hello. I wish to use an online cloud processing service to help compute the larger processes in SNAP. Does the application have an optimal environment to work in?

There is no such service provided by SNAP.
But SNAP is used by several (cloud) processing services. Urban TEP, CODE-DE, CoastColour, …
They are all limited to a certain topic.
A generic processing service is not available, to my knowledge.
Just recently the Copernicus DIAS instances were launched. They could serve such a service. But this would probably need some funding too.

Apologies, it is not an online cloud processing service In cannot find. I wish to know if SNAP has an optimal environment to work in, for example if WIndows, Linux or Mac is preferred. And if it can work better with GPU or best to provide more CPU.

Ah, okay. Now I got it.
The OS is not important for SNAP. But Mac behaves sometimes special. So I would suggest either Linux or Windows,. but in general Mac runs fine too. The GPU is not used for computation. More CPU power is better. Also for the amount of memory, the more the better.
But it depends also on the data. MERIS can easily be processed with 4GB of RAM but for some S1 processings, it is good to have 32GB.