When you block someone on social media, you prevent them from seeing your posts on that social network. Blocked users will also be unable to follow you, message you, or tag you in photos. Blocked Twitter users won’t be able to add you to lists. Blocked users can still @ mention you in a post, but this won’t count toward your engagement metrics.
However, keep in mind that it’s pretty easy even for blocked users to see content you’ve posted publicly. Use the privacy setting on each social network for better control over who sees each of your posts.
Related: Mute, Troll