What is it about?
To generate a Read More… link in WordPress post, you have to write <!–more–> (in HTML view of WordPress wysiwyg text editor) in place where you want to display the link as shown below:

Now I want to point out that this technique will not work in wordpress pages. For example, you create a CMS website in WordPress and you created a custom home page.
Now suppose that you fetched the latest post from News category on the home page. The latest post’s Read More… link will not appear on the home page and it will display the complete post.
In this post you will learn how to make Read More… link to work in WordPress pages.