Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
I’m sorry you’re having trouble with Word activation. Could you please open Word > File > Account and tell exactly what appears under Product Information, including the edition shown and whether it says Unlicensed Product, Activation Required, or something else? Also, please check https://account.microsoft.com/services using the Microsoft account you normally use with Office and confirm whether a Microsoft 365 subscription is listed there as active or expired.
Please also let me know whether Word was purchased as part of a Microsoft 365 subscription, a one-time Office purchase, or provided by your employer/school, and whether you recently changed Microsoft accounts, reinstalled Office, or changed computers.