请问英文邀请函的格式是怎样的？

http://www.invite-o-matic.com/invite-machine.htm
这是一个邀请函的模板，填上你需要的内容就可以了。

你想要什么活动的邀请函呢？我有邀请洽谈的、邀请顺访的、邀请参展的、邀请参会的、邀请座谈的、邀请参加讲座的
Gentleman:

We are pleased to inform you that our new products will be displayed at the International Exposition Center in Toronto to be held from Sept. 1 to 6.

You will find several new methords which should be of special interest to you. Further more, we have introduced substantial improvements in our production line which would also be of interest.

We would be very happy if you would visit our stand number 15 in Exhibit Hall No.2

Enclosed please find 12 tickets for the Exhibition.

Sincerely yours,
×××
上面这个是邀请参加新品展出的