@cfhasan89
Hi there, you are welcome to the Microsoft Tech Community!
For some years, Windows Insider Preview does require a product key as there were some people in the past who were using this insider program to get a free version of Windows.
You will have to enter a product key in order to activate Windows, you can skip this stage but you won't be able to use the personalization settings in the Settings app.
If you had a digital license linked to your Microsoft Account, skip the product key stage completely and then sign in to your Microsoft Account to which the digital license is linked and Windows will be activated.
