How do I create a research question about Harriet Tubman?

Before developing a well-rounded research question, there are several steps that must be taken. The first thing to focus on is the general topic of your essay. Since you already know that the topic is "Harriet Tubman," you can move on to breaking the general topic down into its smaller components. This step is important to creating your research question because it helps to narrow down your general topic about Harriet Tubman to something more specific and focused. To complete this step, ask yourself, "What do I want to know about my topic?" Complete a preliminary research of background information to help you develop questions. Maybe you are interested in knowing about what influenced Harriet Tubman's escape or what role she played in the Civil War. Make a list of all the questions you have about your general topic to help you focus in on a specific and arguable thesis.
Now that you've created a list of questions, your next step is to choose one of these questions on which to focus your essay. Your research question should be constructed as an open ended question. Use question starters such as "why" or "how" to create open ended questions. For your research question to be considered strong, it must be clear (understandable to your audience and easy to research), focused (not too narrow/specific and not too broad/vague), and lead to an arguable thesis.
https://writingcenter.gmu.edu/guides/how-to-write-a-research-question

https://www.esc.edu/online-writing-center/resources/research/research-paper-steps/developing-questions/