Please anybody help in this regards
J.M. Smith, Manager
ABC Company

Dear Mr. Smith,

Would it be possible for me to have a leave of absence for the week of [month, date] to [date]. My daughter is getting married in St. Louis, Missouri, and my participation, including travel, will require that much time.

I would be very grateful for your consideration of this request.

Sincerely yours,

A. Guest

[NB: be sure to give dates and reason, express gratitude--- and submit the request well before a decision is needed.]
For the record:

one week's leave
two weeks' leave