要申請 H-1B 簽證的人首先一定要有一份 「專業工作 (Specialty Occupation)」 聘書。
專業工作 (Specialty Occupation)的定義如下:
"an occupation that requires (a) theoretical and practical application of a body of highly specialized knowledge, and (b) attainment of a bachelor』s or higher degree in the specific specialty (or its equivalent*) as a minimum for entry into the occupation in the United States" [INA§214(i)(1), 8 USC § 1184(i)(1)].