With the Page Scroll Depth feature, you can observe the activity of your user who is visiting your website. You will be able to see the scroll percentage done by your visitors on your website. and you will have a better idea about the interaction of your visitors with your website. In this way, you will be able to improve your content layout and can find a better place for ads to display.
In order to see the Scroll Behaviour inside Google Analytics, You need to log in to the Google Analytics account. and at the same time open your website in incognito mode and make sure you are not logged on your website.