To add risks of physical loss to personal property under form 3, you must have the Homeowners 15 endorsement. Some companies sell a Homeowners form 5 which does the same thing as the combined Homeowners 3 plus the Homeowners 15 endorsement. Other companies have their own risks of physical loss forms they call Special, Gold, Executive etc. Not everyone will qualify for risks of physical loss, but most companies sell the coverage. Your state may have restrictions or natural disaster cause of loss problems.
Coastal states face wind problems.
California, and certain Midwestern areas have severe earthquake problems. Some Western states have brushfire problems. Other areas face hail damage. Each state and company has its own rates and philosophy on how it will insure these common causes of loss. Homeowners 8 Insures for the same causes of loss as the Homeowners 2 form.