It is dispatched to the addressee by the fastest available means. There is no special delivery service on a rural route. Don't send special delivery to an office over a weekend when you know that office won't be open. Special delivery may be purchased on most classes of mail. Special handling service is available for standard class mail only.
Special services vary from country to country.
Most do offer Registry Service or Insurance, and Return Receipts. Return receipt can be used only with a special service. Certified mail not available.