邀請信包括宴會、舞會、晚餐、聚會、婚禮等各種邀請信件，形式上大體分為兩種:一種為正規的格式 (formal correspondence)，亦稱請柬；一種是非正式格式 (informal correspondence), 即一般的邀請信。邀請信是在形式上不如請柬那樣正規，但也是很考究。書寫時應注意:
　　
    邀請信一定要將邀請的時間（年、月、日、鐘點）、地點、場合寫清楚，不能使接信人存在任何疑慮。例如:“I’d like you and Bob to come to Luncheon next Friday.”這句話中所指的是哪個星期五并不明確，所以應加上具體日期, “I’d like you and Bob to come to luncheon next Friday, May the fifth.”

    1. 邀請朋友共進午餐 Inviting a friend to informal luncheon

    Dear [Zhang Ying]:

    Will you come to luncheon on [Friday, May the fifth], at [twelve o’clock]?
My niece [Mary] is visiting us and I think you will enjoy meeting her. She is a charming, very pretty girl … and very good company! [John and Jane] will be here, and perhaps we can [give a dance] after luncheon. Do say you’ll come!
Affectionately yours,
Li Ming

    親愛的[張營]:

    您能在[5月5日星期五中午12點鐘] 來吃午飯嗎？
我侄女[瑪麗]正在我們家中作客，我想您會樂于見到她的。她是個漂亮而聰明的女孩子，……同她在一起是很使人高興的！[約翰和簡]也到這里來，也許在飯后我們能[開個舞會]，說好，一定得來呀！

    2. 邀請朋友同他們不認識的人一起共進晚餐 Inviting friends to supper with the strangers

    Dear [Susan]:

    I know you are interested in [oil painting], so I’m sure you’ll be interested in [Mr. and Mrs. Lin dun]! They are coming here to supper [next Sunday night, October the twelfth], and we’d like you and [Walter] to come, too.
[Mr. and Mrs. Lin Dun] are that very charming couple we met in [London] last summer. They have a wonderful collection of [oil paintings of various stages]; and I understand that Mr. Lin Dun is quite an authority on [oil painting]. I’m sure you and Walter will thoroughly enjoy and evening in their company.
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

    親愛的[蘇珊]:

    我知道您對[油畫]是有興趣的，所以我相信您對林頓夫婦也會感興趣。他們將在[10月12日（下星期日）]來吃飯，我們很希望您和瓦爾特也能同來。

    [林頓夫婦]是那么好的一對夫妻。我們是去年夏天在[倫敦]認識的。他們集有[各個不同時期精美的油畫作品]。我知道，林頓先生在研究[油畫]方面是頗有權威的。我深信，那天晚上您和瓦爾特同他們在一起，一定會很愉快。
我們準備在6點鐘吃晚飯，這樣就能有較長的時間閑談。如果事前接不到您的回信，我就指望你們那天到來。

    3. 邀請參加新廠開工典禮  Invitation to opening ceremony of new factory

    Dear [Mr. Harrison]:

    Our new factory will be commencing production on [April 10] and we should like to invite [you and your wife] to be present at a celebration to mark the occasion.
As you will appreciate this is an important milestone for this organization, and is the result of continued demand for our products, both at home and overseas. We are inviting all those individuals and trust that you will pay us the compliments of accepting.
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,

    親愛的[哈里森先生]:

    本公司新廠將于[4月10日]開始投產，希望能邀請[賢伉儷]來參加新廠開工典禮。
如您所知，新廠的設立是本公司的一個里程碑，而這正是海內外對本公司產品不斷需求的結果。我們邀請了所有對本公司的成功貢獻一切力量的個人，我們相信，您一定會賞光。

    如您確能參加，請來函告知您抵達的時間 ―― 以便我們為您安排會晤。當然，所有安排您在[10日晚間]夜宿的費用，皆將由公司代您支付。

    4. 邀請來家中小住及周末聚會  An invitation for a house and weekend party