If you go to Admin > Census, select the appropriate Census (e.g. Summer 2021) and calculate your School Census if you have not just already done so. On the top right side of your screen click the red button 'Return to Census Page'
Halfway down on the right side you will find 'Official School Summary - HTML Only'
Click on this to bring up your Census Summary, then click on the button in the top Left of the screen which says 'Download page as HTML'
A file will appear at the bottom of your screen, which is the HTML Census Summary. It will be in your downloads folder ready for you to send to its destination.