Mr.Ratna Limbu, generally speaking, the Immgration Department should send you a visa label, then you affixe it onto a blank visa page of your passport for presentation to the immigration officer upon arrival in the HKSAR. However, it send you a letter, you'd better contact the Immigration Department by enquiry hotline at (852) 2824 6111 or by fax at (852) 2877 7711;