Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
Option 1:
You can add personal Microsoft account to Microsoft Store, and then purchase Pro upgrade through it. This upgrade would cost around 99USD.
Option 2:
You can buy Windows 11 Pro retail license directly: https://www.microsoft.com/en-in/d/windows-11-pro/dg7gmgf0d8h4