邀请函又叫请柬，也称请帖，是单位、团体或个人邀请有关人员出席隆重的会议、典礼，参加某些重大活动时发出的礼仪性书信。它不仅表示礼貌庄重，也有凭证作用。

1>格式要求。请柬一般由标题、称谓、正文、落款四部分组成。
标题即用大字书写的“请柬”两字，在第一行中间，或者占用一页，当作封面。
称谓即被请者的单位名称或姓名，另起一行或一页顶格书写，姓名之后写上职务、职称等，如“同志”、“先生”、“教授”、“经理”、“主任”等。
正文应写清活动时间、地点、内容、要求，并用“敬请参加”、“敬候光临”、“敬请届时光临”等语结束。
落款即发函者的署名与发函日期。
2>请柬的形式要美观大方，不可用书信纸或单位的信函纸草草了事，而应用红纸或特制的请柬填写。所用语言应恳切、热诚，文字须准确、简练、文雅。
2、 针对商务或个人：
邀请信（邀请书）
邀请信：邀请信是为了增进友谊，发展业务，邀请客人参加庆典、会议
及各种活动的信函。
1>称谓。
2>开头：向被邀请人简单问候。
3>交待时间、地点和活动内容、邀请原因等。
4>参加活动的细节安排。
5>联系人、电话、地址、落款、日期。
XXX, CEO (被邀请人姓名)
XXX, VP Sales (被邀请人职位)
XXXXXXXX Corporation (被邀请人所在公司)
(Address) (被邀请人所在公司的地址)
It’s our great honor to invite you to visit XXX（活动名称）located at (address) （活动名称）in August, 2003. This visit will provide an opportunity for you to make a better understanding of our marketing issues, and to communicate our future business cooperation in detail. We believe this visit will be of great benefit to our future business cooperation.
Please use this invitation letter to attend our activity.
We are all looking forward to seeing you soon, and should you have any questions, please feel free to inform me.
Yours truly,
XXX (邀请人姓名)
Vice President Sales (邀请人职务)
XXX Company (邀请人公司名称)
Dear sir/madam:
Thank you for your letter of [date]（来信日期）. I'm glad that you are also going to [place] （活动地点）next month. It would be a great pleasure to meet you at the [exhibition/trade fair]（展览名称）.
Our company is having a reception at [hotel] （酒店名称）on the evening of [date] （日期）and I would be very pleased if you could attend.
I look forward to hearing from you soon.
Yours sincerely,
[name]
[title]
邀请参加演讲：
Dear sir/madam:
I'm delighted you have accepted our invitation to speak at the Conference （会议题目） in [city] （城市）on [date]（日期）.
As we agreed, you'll be speaking on the topic ""（演讲题目） from [time] to [time]（演讲起止时间）. There will be an additional minutes for questions（安排提问时间）.
Would you please tell me what kind of audio-visual equipment you'll need（是否需要演讲设备）. If you could let me know your specific requirements by [date]（最晚知晓日期）, I'll have plenty of time to make sure that the hotel provides you with what you need.
Thank you again for agreeing to speak. I look forward to hearing from you.
Sincerely yours,
[name]
[title]
We would like to invite you to an exclusive presentation of our （推介会名称）. The presentation will take place at [location]（活动地点）, at [time] （活动时间）on [date] （活动日期）. There will also be a reception at [time]（签到处开放时间）. We hope you and your colleagues will be able to attend.
[company]（公司名称） is a leading company of high-quality . As you well know, our recent marketing activities have made increasingly affordable to the public. Our new activities this year offer superb quality and sophistication with economy, and their new features give them distinct advantages over similar activities from other media (对报系本年度活动的赞美) .
We look forward to seeing you on [date] (活动日期) . Just call our office at [phone number]（办公电话号码） and we will be glad to secure a place for you.
Sincerely yours,
[name]
[title]