Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
To install on a new PC, use your associated Microsoft account. Go to https://account.microsoft.com/services and sign in with your credentials.
Note that one-time purchase (sometimes referred to as perpetual) licenses can only be installed on one computer at a time.
If you need assistance with activation, see https://support.microsoft.com/en-us/windows/activation/activate-microsoft-perpetual-products-using-the-product-activation-portal .