About Z Visa

Hello Sir/Madam

I am from Pakistan, Recently, I am in Shanghai. I completed my Ph.D. I got job here, My university believed that I will get residence permit and they gave me work permit card. When I went to apply for residence permit in Shanghai, They told me, I need to apply for Z visa from Pakistan then come back again then they will give me residence permit. I wish to know that If I come to Pakistan now then Can i get Z visa from karachi ? and what documents are required ?

Thank you so much