Students often see a thesis statement as an object of mystery. It helps to realize that they are friend, not foe. They are often quite useful tools, both in helping you write and in making sure the final product is powerful.
Simply put, a thesis tells the reader your topic and your position on that topic.
When you’ve decided on a topic and explored it with prewriting activities, drafting a working thesis is a very helpful next step. As the name implies, a working thesis is a work in progress–it helps you form initial ideas, but is open to change as you keep working on the project.
A working thesis statement is just like a regular thesis statement, except that you can tweak it and change it as you research and write. It’s sort of like making a plan for the weekend on Tuesday night: you know the plan will probably be modified, but it’s a good place to start. — Portland State University Writing Center