informal letter of invitation
dear miss smith,
my brother peter will be staying with us for a few days during the christmas holidays and my wife and i have planned a family dinner for him next saturday evening at seven oclock so that he can meet some of our friends . we should be delighted if you could join us. i hope you will let me know that you can come.
formal letters of invitation
mr. and mrs. andrew k.k. wang request the pleasure of your company at a dinner in honor of their parents fiftieth wedding anniversary on sunday, the fifth of july at eight oclock new asia hotel 100 deep water bay road
r. s. v. p.