If I'm not mistaken, the US does not have direct democracy for presidential elections (https://www.usa.gov/electoral-college) nor the lawmaking process (https://www.usa.gov/how-laws-are-made). Unless you're referring other forms of direct democracy in the US (https://ballotpedia.org/Forms_of_direct_democracy_in_the_American_states) or elsewhere in the world like Russian presidential elections.

As for how China's president is elected, these two videos basically sum it up:

• How deputies are elected to people's congresses https://news.cgtn.com/news/2023-02-24/How-deputies-are-elected-to-China-s-people-s-congresses-1hGaCLluMtW/index.html
• How are Chinese leaders elected? https://news.cgtn.com/news/3267444d7a6b7a6333566d54/index.html