Hello Araya Sol,
Thank you for posting your question on Microsoft Q&A forum
Since Q&A assist already provided all the step to reinstall Word. You also mentioned that your word is not working and need to reinstall, so I would like to refer you to this site:
https://learn.microsoft.com/en-us/officeupdates/update-history-office-for-mac
You can look for every version of Office app for MacOS on here to download if the newest version not working for you.
Feel free reply back to this post if you need further assistance, I'll be happy to assist.