A Company, in it’s simplest form, is a collection Contacts.
A Company can include only one Contact, or it can include hundreds, or anywhere in between (depending on your particular license level).
A Company can have Notes, Events, and Goals added to it, similar to individual Contacts.
This allows you to track and save information related to a Company, separate from the Contacts (in the event that the assigned Contacts change later).
Additionally, Contacts can be added and removed from Companies freely. Assigning Contacts to Companies allows you to more easily keep track of communication and metrics related to these Contacts.