Extensions allow you to create as many custom fields as you need, for each type of record. That means your "Project" work might have 3 or 4 custom fields you need to record, whereas your "Consulting" work might have 10 completely different data fields.
Custom Fields allow you to define more fields, on a type by
type basis, for prospects, jobs, issues and more in
On the main navigation bar, hover the module you wish to
configure extra fields for, and then click *Config. *Note
you must be an admin user to access this feature.
A field type allows you to define what kind of information
the field should hold, such as text, numbers, currency,
dates, a picklist, and even a contact or staff member.