给外商来工厂参观的邀请函怎么写，是不是有什么固定的格式，急用，谢谢

Dear Sir,

We are pleased to invite xxx to visit our factory for business negotiation and, we sincerely hope that the coming visit will make a deep impression on you about our factory.

We shall make all necessary arrangement for your visit and, in the same times, we understand that all expenses of your visit, including accommodations, air tickets as well as health insurance, will be on your account.

We are looking forward to meeting you in the near future.

Best regards,
xxx

补充答复：
邀请函是客户拿着去申请办理来中国签证或其他相应手续的，此类邀请函不需要向国内政府机关申请备案的，对形式和所用纸张也没有规定。当然，如果国外客户提出对邀请函的具体要求，如果你能办到，就尽量办。一般来说，以上这个形式足够了。

没有固定格式。。