Mail — often called post — refers to items carried through a postal network: letters, printed documents, and small to medium packages. Anything handed into that network for collection and delivery is called mail or post. The simplest elements of the system are a sender, an item to send, postage to pay and an address. Traditionally, postage is evidenced by a stamp or label and processed by post offices and postal workers.

Core features and components

Postal systems handle multiple item types and services. Typical categories include letters and postcards, domestic and international parcels, registered and insured mail, and bulk mailings. Postal infrastructure commonly contains post offices, sorting centers, delivery routes, collection boxes and a roster of postal staff and vehicles. The basic user actions are to prepare an item, affix postage, deposit it in a public collection box or hand it to a postal counter, and await delivery to the recipient's address.

Many postal services also provide additional functions. Examples are money orders and basic banking, government document distribution and processing, and forms of identity or license delivery. Historically, in some countries the post office administered telegraph or telephone networks; some modern postal operators still offer a range of non-postal retail and financial services. For an overview of typical documents handled, see documents and letters; for parcel examples, see parcel services. Global delivery considerations are addressed via international postal agreements.

Organization and regulation

Postal systems may be public (state-run) or private; in many countries governments either operate the national postal service or tightly regulate it. Since the 19th century, national authorities commonly established monopoly or universal service obligations to ensure delivery to remote areas and to set standard rates. Governments typically control standards, licensing and consumer protections, and in some jurisdictions maintain exclusive rights for certain classes of mail. For how governments interact with postal providers, see government roles and the use of fees and stamps described at postage and fees.

History and development

Organized mail systems date back centuries, evolving from couriers and relay riders to modern networks of rail, road, air and automated sorting. The introduction of adhesive postage stamps in the 19th century simplified prepayment and accounting, while international cooperation (agreements and unions) enabled standardized cross-border delivery. Technological changes — mechanized sorting, air transport and trackable labels — progressively increased speed and reliability. The postal sector later adapted to competition from private couriers and to reduced letter volumes following the rise of electronic messaging; see distinctions from non-postal carriers at couriers and carriers.

Common uses and importance

Mail remains important for official communications, legal notices, signed deliveries, direct-mail marketing, and the movement of goods bought online, particularly where local logistics or payment infrastructure prefer physical services. Post offices often serve as community access points for financial transactions, bill payments and government services such as passport application or license distribution — examples include passport services and driver's license delivery. In regions with limited banking, postal banking is a vital service; read more at postal banking and available local services at post office services.

Delivery methods and distinctions

  • Collection: items are dropped in a public post box or handed in at a counter.
  • Sorting and transit: centralized processing centers sort by destination and route.
  • Transport: road, rail and air carry mail between hubs; last-mile delivery completes the route.

Different products and protections exist: tracked or registered mail for proof of delivery, insured parcels for valuable contents, and priority or airmail for speed. Postal services differ from private couriers by universal-service obligations, regulated pricing or exclusive rights for certain items. For a guide to international rules and agreements, consult country postal differences and historical telecom links at telegraph and telephone ties.

Despite digital alternatives, physical mail continues to move millions of pieces daily, adapting through parcel innovations, improved tracking and integration with e-commerce logistics. For operational examples and practical tips, see regulatory frameworks and user guidance at postage guidance.