should be sent immediately upon the occurrence of the fortunate
event that calls forth congratulatory wishes; they should be brief,
gracefully worded and contain no mention of other matter. The occasions
in life that call forth such missives are numerous: birthdays,
engagements, marriages, anniversaries, business successes, etc.,
each, or all, should win some congratulatory notice. The formal
congratulation is in set terms, usually written in the third person,
and may be used between individuals but slightly acquainted; for
example:
Mr. and Mrs. Stuart congratulate Mr. and Mrs. Fielding upon the
successful conclusion of Mr. Harold Fielding’s college course and
express the pleasure with which they listened to the delivery of his
eloquent oration on Commencement Day.