The important thing to remember is that word order is the same in Chinese for questions and statements.
Placement of question words, Chinese Grammar Wiki
While the Chinese Grammar Wiki says this, it doesn't give a single example where 什么 is the subject of a question. It feels like it's ungrammatical a lot of the time:
什么是这？ (What is this?)
什么是我的名字？ (What is your name?)
什么是你最喜欢的颜色？ (What is your favorite color?)
什么是你的水平？ (What is your level?)
什么是一加一？ (What is one plus one?)
But sometimes it seems okay:
什么是美？ (What is beauty?)
什么是百度？ (What is Baidu?)
什么是气候变化？ (What is climate change?)
I'm not precisely sure, but it appears we can ask questions like "什么是[pla pla]？" when "[pla pla]" is some abstract, unfamiliar, or needing-to-be-defined concept.
Question: When can we start a question with 什么是……?