If you could not find your university on the list, the administrator of your school should create the Office 365 tenant account as oscarmh suggested. Then you could enter a valid school email address in this page to try to get started with Microsoft 365 Education.
According to your comment, do you remember the "office 365 acc"?
You may go to Services & subscriptions, check if there is any Office product that you have.
Please also sign it in to www.office.com, find whether there is a "Install Office" button.
If yes, please refer to the article "Download and install or reinstall Microsoft 365 or Office 2019 on a PC or Mac".
If not, this account is not associated with the relevant Office license. You could not use this account to install or activate Office currently.
Anything unclear please let us know.
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