A letter is the most common method of information exchange; it brings together a huge group of documents of very different content, distinguished by the way the text is transmitted (by mail). Letters make up a large part of the incoming and outgoing documents of any institution and have many varieties.

Types of letters:
instructional;
accompanying;
information;
guarantees;
advertising;
claims;
arbitration;
confirmation letters;
reminder letters;
notification letters;
letters of request.

Letters express congratulations, wishes, greetings on solemn occasions. Letters are sent as a sign of participation and expression of condolence in dramatic and tragic situations.

The letter is written on a specially designed for this type of document in A4 format. If the text of the letter does not exceed seven lines, it is allowed to use A5 format for letters.

The date of the letter is the date of its signing.

The text of the letter follows the scheme:

Introduction (here are the motives for drafting the letter, references to events, facts, decisions of higher institutions and other factors that served as the basis for drafting the letter);
Evidence (where the rationale for the issue set out in the letter is set out);
Conclusion (listing conclusions, requests, demands, suggestions).
Often in the practice of documentation are used letters which contain one final part of the text without explanations.

As a rule, the text of the letter should not exceed one page.

The purpose of drafting and sending letters is reduced, as a rule, to motives, hence the main requirements to the text: clarity, precision, brevity of presentation. The practice of correspondence has developed several general rules that must be adhered to in the preparation and design of letters.

A letter should be devoted to one issue, which simplifies the operations of their processing and speeds up execution in the organization to which they are addressed.

The “text of the letter is usually” stated in the third person singular, for example: “The school does not have the opportunity to …”, “In the coming year the school does not expect …”, etc.

The right to sign official letters, as a rule, belongs to the head, and in his absence (illness, vacation, business trip) to his deputy or an official acting head. Letters are sent nowadays not only by mail, but also by telegraph, facsimile machines, computer networks (e-mail).

Regardless of how the document is sent, there are unified requirements for its drafting and execution.