It's unlikely that Windows 12 will be totally free. Similar to how Windows 10 users were upgraded to Windows 11, users with a valid Windows 11 license would be eligible for a free upgrade if Microsoft adopts its previous strategy. New users or those using previous versions, such as Windows 7 or 8, might have to buy a new license, nevertheless. Its pricing may also be influenced by subscription-based business models, such Microsoft 365 integration. Microsoft has not yet confirmed
windows 12 release date so everything is just based on industry leader’s prediction.