Do check out Zoho Annotator. It's a clean and very easy-to-use tool that lets you take screenshots of web pages and add annotations to them. It even has the functionality to let you share your final screenshots via social media, email, or cloud storage built-in.
@marie_martens Thanks for the recommendation. My bad! I should have mentioned that I am looking for Windows. But I was looking at their features list, they are providing cool utilities.