Windows Agent List of Registry Keys and Interactions With Other Processes to do the Inventory

Hi,

In order to perform the inventory, how does the agent to obtain information about the properties of the computer? For example, the list of installed software, the list of running processes ...
Is it through the windows registry? If yes, what are the registry keys?
Is there a windows process with which the agent needs to communicate or access to get the inventory?
I'm looking for help because I need to install the agent on computers running Windows that runs software that controls the installed applications and I need to provide those details.
I used the Proccess Monitor from the sysinternals suite of Microsoft to monitor access to the registry but despite seeing several accesses to the registry made by the agent, in fact I do not know what relevant information I should pass.
Any documentation pointing the direction is also very welcome.

Thanks in advance.