Apology is expressing your regret on not doing something, an apology can be for an incomplete work , for a damage , delay, an error, breach of trust, for hurting feelings, for an offensive behavior or anything like this. It is good to apologize as early as it is possible. A letter of apology can be written in both formal and informal way. The formal or official note of apology, saying sorry to others remains formal, the language, style and presentation of letter brings formality to the letter. Such a letter is written to business circles, groups or the companies and even to individuals, those we think deserve a certain respect.
A formal apology requires some extra elements of regret on not completing a task. A formal apology should also be typed and written on a quality paper. It must be concise and to the point, it should cover all the areas which gave rise to the situation and clear your position, but you should not try to justify yourself. An informal letter of sorry is usually in a friendly or more casual tone. Following are some of the points which should be focused while writing a letter of apology.
Your letter should be clear, without any ambiguity, the tone should be amiable. Mention your mistake and be very open and clear about your mistake, you should also mention that you know how much hurting your act would have been for the recipient, it will be wise to mention that you never intended it this way. Mention that what inconvenience was caused by your act will not be repeated in the future and you really care about it. Tell that you did not intend to hurt the reader or cause damage which leads to mental disturbance and chaos for others in any sense. Finish your letter while reassuring that you feel the wrong done. Sample of the letter of apology is attached with this template for the help of the readers.