Congratulations wedding letter is written to convey best wishes to an individual on his/her marriage or wedding in his/her family. The letter is used to express you heartfelt joy for the occasion. The mood and format of the letter will depend on the association between the two parties. It should be warm, convey your genuine feeling of happiness and express your praise. The letter can be used to congratulate the individual after the event is complete if you could not be present during the occasion personally or in anticipation of the same.