Do you apply for marriage immigration in the United States by calling the embassy directly or making an appointment with the immigration bureau later?

If the marriage certificate is in English, notarization is not required. Your husband needs to go to the consulate in person to submit the application (if you are in Beijing or Guangzhou, you can pay directly, if you are in other consulates, you can only pay and send the application materials to Beijing or Guangzhou (the consulate staff will tell you where to send them). As for the preparation of materials, it's a long story, but don't hire an intermediary or a lawyer, especially since you are IR 1, the fastest type of all immigrants in China. Search 00 1 on Google.

American Marriage and Immigration Mutual Assistance Forum (an ugly but very, very real forum full of mutual assistance posts of people who are or have been engaged in marriage and immigration). Good luck!