In Lead type tab you can see four preset lead types which you can neither edit nor delete. These lead types get assigned automatically to the leads who got to the system by submitting a form, or making a purchase, or registering someone on your site, or downloading something. You can also configure your own lead types for those leads who get added to the CRM manually. You can even choose a default lead type that will be added to any new manually created lead by default. Lead types for any particular harvesting can be assigned automatically or set on your Leads screen.