邀请信的格式如下：
开头即表明邀请原因，邀请对方参加活动。邀请信中间要介绍活动的具体内容，强调活动的意义，表明参加这项活动的必要性，使得邀请成功。信的结尾，请期待对方尽早确定是否参与，并给自己回复。
正文
Dear Wangcai,
I am greatly honored to formally invite you to participate in Mr. Old Fish’s wedding ceremony with Ms. Fujiwora to be held at Beijing Grand Hotel from 8 to 10 p.m. on April 1, 2019.
As you are a close friend of us, we would very much like you to attend the celebration and share our joy. The occasion will start at seven o’clock in the evening, with the showing of their wedding ceremony.
This will be followed by a dinner party. At around ten, we will hold a small musical soiree, at which a band will perform some works by Bach and Strauss.
If you do not have any prior appointment on April 1, we look forward to the pleasure of your company.
Yours sincerely,
Li Ming
亲爱的王采：
我非常荣幸地正式邀请您参加2019年4月1日晚8点至10点在北京大酒店举行的老鱼先生与藤原爱女士的婚礼。
由于您是我们的好朋友，我们非常希望您能参加我们的庆祝活动并分享我们的喜悦。婚礼将在晚上七点开始，届时他们将举行婚礼。
接下来是一个晚宴。十点左右，我们将举行一个小型音乐晚会，由一个乐队演奏巴赫和施特劳斯的一些作品。如果您在4月1日没有任何预约，我们期待着您的光临。
李明
