My wife can access her email (the server is Outlook 365) from her computer. But when I tried to sign on to her account from my computer, it rejects the password she thought she was using. And she cannot change the password except by typing in the old one, which she apparently doesn’t know. So I ask is there any way to see the cookie that contains her saved password?
Presuming she is accessing through a web browser, there are various instructions here.
She might reset the password:
That is not a Microsoft site and I would not trust it.
office.com is the Microsoft 365 login site. There must be a password reset feature without having to call anyone. You may have had to provide a secondary email address when you signed up, or possibly a mobile phone for an SMS message.
Wikihow has instructions for reading the cookies from whatever major browser one may be using; look for cookies on “office.com” and/or “live.com”.
P.S. – best to Dors. 
Dors returns your greetings. The quoted site does not work; at one point, the screen is different. But the dashline site in the first post does give explicit instructions and I have now got her correct password. You would think a robot would never forget.
The Dope is great!