Regarding project submission for exam

Should I have to submit the capstone project as the project for exam or should I make another project for exam?

You can submit capstone project as final project or you can also take help from the website to get knowledge of different projects. You can get basic ideas to build your own project from the website.

You don’t have to submit the Capstone project as the project of your exam. It is just for self evaluation but if you want you can. You may want to check out other projects or get new project ideas before final submission. For this you can visit the bolt iot hackster page. Here is the link:
Hope it helped!