一、普通英文邀请函
第一种邀请信邀请的对象一般是朋友、熟人，所以内容格式上的要求都比较松，可以写得随便一些。只要表明邀请的意图，说明活动的内容、时间、地点等等。但既然是邀请信，那么就一定要在信中表达非常希望对方能够参加或者出席的愿望。这种邀请信的篇幅可以非常短，下面以一封邀请看电影的短信为例：
Dear Jane,
We have four tickets for a famous film shown at Guangming Cinema, TheLongest Day, Friday, the ninth. Will you join us? We'll be looking for youat eight sharp Friday night in front of the cinema, so don't disappoint
us!
Warmest regards.
Alice
二、正式英文邀请函
第二种邀请信一般由会议或学术活动的组委会的某一个负责人来写，以组委会的名义发出，而且被邀请者通常也是属于比较有威望的人士。因此，这类邀请信的措辞要相对正式一些，语气要热情有礼。
这一类邀请信通常要包括以下内容：首先表明邀请对方参加的意图以及会议或学术活动的名称、时间、地点;然后要对被邀请者的威望和学术水平等表示推崇和赞赏，表明如果被邀请者能够接受邀请，会给会议或者活动带来很好的影响;接着要说明会议或活动的相关事宜，最好是能引起对方兴趣的事宜;当然不能忘了表达希望对方能够参加的诚意;最后还要请收信人对发出的邀请做出反馈，如确认接受邀请。下面是一封邀请对方参加学术会议的信函：
Dear Professor Wang,
On behalf of the Ohio State University and the IEEE Computer Society, Iwould be very pleased to invite you to attend and chair a session of theforthcoming 2004 International Conference on Parallel Data Processing tobe held in Bellaire, Michigan, from October 25 to October 28, 2004.You are an internationally acclaimed scholar and educator. Yourparticipation will be among the highlights of the Conference.
We sincerely hope that you could accept our invitation. As you know, this is the 10th anniversary of the Conference and we plan to make it a truly international meeting. We have accepted many papers from several foreign countries, including two from China.
If you can come, please let us know as soon as possible, since we have to prepare the final program soon. We are looking forward to your acceptance.
Sincerely yours,
Peter White