Apple Computer and Microsoft Office

I have an Apple MacBook Pro computer (purchased in November 2014) and back in 2019 I subscribed to the Microsoft Office suite, including Microsoft Word, Excel and Power Point programs. The reason I signed up for the Microsoft products was so that I could access my then-work email address, as well as use those Microsoft programs I needed for work. I continue to use those Microsoft programs since leaving that job. For some reason, however, I cannot access Microsoft Office for use in managing e-mails without the computer asking me for a keychain access code, which I don't have. How can I access Microsoft office so that I can drop the old work e-mail address and change the relevant e-mail address to include my personal address and the one for my new solo law firm? Any help would be appreciated.