Visiting boyfriend and he indicated that I'll undergo an interview at the embassy.

Usually, the consular officers may inquire your basic personal information and your detailed travel itinerary such as why you go to China, how long you will stay, which city you will go etc.
If you plan to apply for a tourist L visa, you need to submit those documents including passport and copy of its data page, a completed application form attached with a passport-style photo, transportation arrangement and an invitation letter from your boyfriend.