邀請信分為兩種：一種屬于個人信函，例如邀請某人共進晚餐、參加宴會、觀看電影、出席典禮等。另一種邀請信則屬于事務信函，一般是邀請參加會議、學術活動等等。
一、普通邀請信
第一種邀請信邀請的對象一般是朋友、熟人，所以內容格式上的要求都比較松，可以寫得隨便一些。只要表明邀請的意圖，說明活動的內容、時間、地點等等。但既然是邀請信，那么就一定要在信中表達非常希望對方能夠參加或者出席的愿望。這種邀請信的篇幅可以非常短，下面以一封邀請看電影的短信為例：
Dear Jane,
We have four tickets for a famous film shown at Guangming Cinema, The Longest Day, Friday, the ninth. Will you join us? We'll be looking for you at eight sharp Friday night in front of the cinema, so don't disappoint us!
Warmest regards.
Alice
二、正式邀請信
第二種邀請信一般由會議或學術活動的組委會的某一個負責人來寫，以組委會的名義發出，而且被邀請者通常也是屬于比較有威望的人士。因此，這類邀請信的措辭要相對正式一些，語氣要熱情有禮。
這一類邀請信通常要包括以下內容：首先表明邀請對方參加的意圖以及會議或學術活動的名稱、時間、地點;然后要對被邀請者的威望和學術水平等表示推崇和贊賞，表明如果被邀請者能夠接受邀請，會給會議或者活動帶來很好的影響;接著要說明會議或活動的相關事宜，最好是能引起對方興趣的事宜;當然不能忘了表達希望對方能夠參加的誠意;最后還要請收信人對發出的邀請做出反饋，如確認接受邀請。下面是一封邀請對方參加學術會議的信函：
Dear Professor Wang,
On behalf of the Ohio State University and the IEEE Computer Society, I would be very pleased to invite you to attend and chair a session of the forthcoming 2004 International Conference on Parallel Data Processing to be held in Bellaire, Michigan, from October 25 to October 28, 2004.
You are an internationally acclaimed scholar and educator. Your participation 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
三、邀請信的回復
無論是收到哪種邀請信都要復信，明確表示接受與否。而且無論接受與否都要對邀請者表示感謝。接受邀請的回信一般包含以下內容：首先感謝對方的邀請，并重述邀請信中的主要內容;然后愉快地表示接受邀請，并簡要說明自己的打算;最后表示期待赴會和與對方見面的心情。下面是一封接受邀請的信，與上面第一封邀請信相對應：
Dear Alice,
Thank you very much for your invitation. It will be great pleasure for me to join you on Friday for the wonderful film. I will arrive at the cinema before eight. I look forward to meeting you on Friday.
Thank you for thinking of me.
Yours,
Jane
謝絕邀請的回信一般包含以下幾方面的內容：首先還是要對對方的邀請表示感謝;然后具體說明自己無法接受邀請的原因，并對無法出席表示遺憾;最后表達自己的祝愿，即祝愿自己未能參加的會議或者活動能夠順利進行。下面是一封謝絕邀請的信，與上面的第二封邀請信相對應：
Dear Professor White,
Many thanks for your letter dated 15th August, inviting me to attend and chair a session of the forthcoming 2004 International Conference on Parallel Data Processing to be held in Bellaire, Michigan, from October 25 to 28, 2004.
Much to my regret, I shall not be able to honor the invitation because I have been suffering from a disease since this summer. I am firmly advised that it would be unwise to undertake any distant and long travel in the near future.
I feel very sad to miss the opportunity of meeting you and many others in the field of Computer Science. I wish the conference a complete success.
Faithfully yours,
Wang Xuan
