If you don’t have MS Office login details you need to create one Microsoft account and then login.Now you need to Enter your Microsoft login details like username and password.(MS Office, MS Excel, MS PowerPoint, etc) Now Click on the extension and choose any MS 365 product you want to use.Now the extension will be listed at the top right corner of the browser.Now Search “ Microsoft 365” on the Chrome Web Store Search Bar.You can search Chrome store on the browser and click on the 1st link.