Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
Thank you Jim. In the meantime I bought a new licence and installed it on my new Mac. I did upgrade the old one to the latest version (prior to moving my files across), which I suppose is what caused the problem... I just wish someone (at the Apple store) would have told me before investing into my new laptop i.e. making me aware, as it would have saved me hours of hassle and headache...