Jamaican family on Instructor/Dependent visa

Hello. I am Jamaica working in Japan on Instructors entry permit. My Jamaican family *(husband, wife, 3yr old daughter) and I live in Aomori and want to visit Beijing for a month. I know we need entry permit but where do I apply? And what type to apply for. Sapporo is too far. Also, would we be able to apply online and mail passports to them? Can only 1 person take all the passports if we have to apply in person?