The General Ledger is a detailed report for all transactions posted to each account and for every transaction there is a Credit and Debit account so it lists them all up.
A company is a legal entity made up of an association of people for carrying on a commercial or industrial enterprise.
In Parsimony, the first Company is created when a Parsimony account is set up. For each Company, you can set a domain as manufacturing, retail, or services depending on the nature of your business activity.