邀请信在形式上大体分为两种：1. 正规的格式 (formal correspondence)，亦称请柬；2. 非正式格式 (informal correspondence), 即一般的邀请信。
邀请信在形式上不如请柬那样正规，但也很考究,书写时应将邀请的时间（年、月、日、钟点）、地点、场合写清楚.范例1 ：? 邀请参加新厂开工典礼dear [mr. harrison]:please confirm that you will be able to attend by advising us of your time —— we can arrange for you to be met. all arrangements for your stay [overnight on april 10] will, of course, be made by us at our expense.yours faithfully,亲爱的[哈里森先生]:本公司新厂将于[4月10日]开始投产，希望能邀请[贤伉俪]来参加新厂开工典礼。
如您所知，新厂的设立是本公司的一个里程碑，而这正是海内外对本公司产品不断需求的结果。
我们邀请了所有对本公司的成功贡献一切力量的个人，我们相信，您一定会赏光。
如您确能参加，请来函告知您抵达的时间——以便我们为您安排会晤。
当然，所有安排您在[10日晚间]夜宿的费用，皆将由公司代您支付。
范例2：? 邀请朋友同他们不认识的人一起共进晚餐dear [susan]:we’re planning supper at six; that will give us a nice long evening to talk. if i don’t hear from you before then, i’ll be expecting you on the [twelfth]! affectionately yours,li ming范例3：? 邀请朋友共进午餐 inviting a friend to informal luncheondear [zhang ying]:my niece [mary] is visiting us and i think you will enjoy meeting her. she is a charming, veryaffectionately yours,li ming范例4：邀请参加展会dear sirs/madam:we’re one of the manufacturers specialized in sanitaryware, concluding one & two piece toilet, wash basin, cabinet basin, pedestal basin, bidet, urinal, counter basin , decorated ceramics and so on. our new models offer superb design and their new features give them distinct advantages over similar products from other manufacturers.exhibition center : the continental exhibition centerbooth number : g-k105 g-k-106date : apr 15th to 20th 2006best regards五种常见的英文邀请信1) 请对方来发表一个speech，这封信是要感谢对方，同时确认对方对技术设备的具体要求。
dear sir/madam,im delighted you have accepted our invitation to speak at the conference in [city] on[date].as we agreed, youll be speaking on the topic from [time] to [time]. there will be some time for questions.would you please tell me what kind of audio-visual equipment youll need? if you could let me know your specific requirements by [date], ill 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]2) 这封信则是请对方来参加自己公司的一个招待会。
dear sir/madam,thank you for your letter of [date]. im glad that you are also going to [place] next month. it would be a great pleasure to meet you at the [exhibition/trade fair].i look forward to hearing from you soon.yours sincerely,[name][title]3) 这封信是邀请对方公司派人来做介绍。
dear sir/madam,sincerely yours,[name][title]4) 邀请收信人参加自己公司的产品演示会。
dear sir/madam,we would like to invite you to an exclusive presentation of our new [product]. the presentation will take place at [location], at [time] on [date]. there will also be a reception at [time]. we hope you and your colleagues will be able to attend. we look forward to seeing you on [date]. just call our office at [phone number] and we will be glad to secure a place for you.sincerely yours,[name][title]5) 邀请收信人参加公司总裁的退休仪式，这也是公司人性化公关活动的一种形式。
dear sir/madam,[location], on [date] from [time] to [time].正式邀请信邀请信分为两种：一种属于个人信函，例如邀请某人共进晚餐、参加宴会、观看电影、出席典礼等。
另一种邀请信则属于事务信函，一般是邀请参加会议、学术活动等等。
一、普通邀请信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, the longest day, friday, the ninth. will you join us? well be looking for you at eight sharp friday night in front of the cinema, so dont disappoint us!warmest regards.alice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,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.sincerely yours,peter white三、邀请信的回复无论是收到哪种邀请信都要复信，明确表示接受与否。
而且无论接受与否都要对邀请者表示感谢。
接受邀请的回信一般包含以下内容：首先感谢对方的邀请，并重述邀请信中的主要内容；然后愉快地表示接受邀请，并简要说明自己的打算；最后表示期待赴会和与对方见面的心情。
下面是一封接受邀请的信，与上面第一封邀请信相对应：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谢绝邀请的回信一般包含以下几方面的内容：首先还是要对对方的邀请表示感谢；然后具体说明自己无法接受邀请的原因，并对无法出席表示遗憾；最后表达自己的祝愿，即祝愿自己未能参加的会议或者活动能够顺利进行。