[Your letterhead, if desired; if not, your return address]
[Date of letter-month, day, and year]
[Recipient's first and last names]
[Street or P.O. box address]
[City, State ZIP code]
Dear [recipient's name]:
Our parents, Margie and Carl, will be celebrating 30 years of marriage on July 5th. I'm sure they can't believe how quickly the happy years have flown by since they said their vows in Cascade City. As their anniversary draws near, we plan to honor them with a special celebration party, so stay tuned for further details on that.
We are so grateful for the love you have shown to our parents and our entire family.
[Sender's first and last names]