There is no fixed requirement for the headline and subtitle of a Chinese paper, which mainly depends on the content of your article, but if all the headlines are written together, it will definitely affect the logic of the article. If you list them, there must be more than three. It depends on how many titles your content is divided into. You can go to HowNet and search for several documents related to your direction.

The title of the paper requires:

First-class title: the title number is "I", No.4 is in bold, exclusive, and there is no punctuation at the end.

Second-level title: the title serial number is "(1)", which is the same as the font size of the text, and it is a special line with no punctuation at the end.

Third-level title: the title serial number is "1." , the same size and font as the text.

Four-level title: the title serial number is "(1)", which is the same as the text size and font.

Five-level title: the title serial number is "①", which is the same as the font size and font of the text.

Refer to the above? Baidu encyclopedia-paper format