1) 請對方來發表一個speech，這封信是要感謝對方，同時確認對方對技術裝置的具體要求。
Dear Sir/Madam,
I'm delighted you have accepted our invitation to speak at the conference in [city] on [date].
As we agreed, you'll 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 you'll need? If you could let me know your specific requirements by [date], 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]
2) 這封信則是請對方來參加自己公司的'一個招待會。
Dear Sir/Madam,
Thank you for your letter of [date]. I'm glad that you are also going to [place] next month. It would be a great pleasure to meet you at the [exhibition/trade fair].
Our company is having a reception at [hotel] on the evening of [date] and I would be very pleased if you could attend.
I look forward to hearing from you soon.
Yours sincerely,
[name]
[title]
3) 這封信是邀請對方公司派人來做介紹。
Dear Sir/Madam,
[Organization] would very much like to have someone from your company speak at our conference on [topic].
As you may be aware, the mission of our association is promotion. Many of our members are interested in the achievements your company has made.
Enclosed is our preliminary schedule for the conference that will be reviewed in the coming weeks. I'll call you [date] to see who from your company would be willing to speak to us. I can assure you that we'll make everything as convenient as possible for the speaker.
Sincerely yours,
[name]
[title]
4) 邀請收信人蔘加自己公司的產品演示會。