Creating New Contacts
From the Main CiviCRM screen there are several options for creating new contacts. Depending on your Main CiviCRM screen configuration, there are usually SHORTCUTS for New Individual, New Organization and New Household. Some configurations can also provide a section for "QUICK ADD" blocks for quickly filling in the name and email address fields.
To avoid adding duplicate contacts, see Find and Merge Duplicate Contacts
The THREE types of CONTACTS you can create are (click for more info):