Which type of mail includes all correspondence, whether hand written or typed, all bills, and all materials sealed against postal inspection and weighing 13 ounces or less?

First class mail

Explanation:

First class Mail are known to include all personal correspondence, bills and statement of accounts, any sealed material or any material sealed against any form of postal inspection, and all material that is writing partly or wholly or typewritten, and weighs 13 oz or less. Any piece found to weigh over 13 oz is classified as a Priority Mail.

FIRST CLASS MAIL

Explanation:

First-class mail is used for postcards, letters, large envelopes, and small packages. First-class mail must weigh 13 ounces or less. First-class delivery is given priority over standard mail, and local mail because they weigh less.

First class mail is the most popular and economical way to send standard postcards, letters, large envelopes, all Bills and all materials sealed against postal inspection.