I bought my laptop last Sep 2019 and it's only now that I need to use MS Office It has Office 365 installed but I need to activate it in order to edit office docs (I can only open)

Can anyone help me on how I can get a key for this or if I need to uninstall this and install a new MS Office? Dati kasi I was lent an MS office CD but I don't remember now who lent me (that was in 2013)