Manual WordPress Excerpts are the hand-crafted summaries of your content that can be used in your theme. It is unlike to automatic excerpt or you can say teaser which is actually the part of your post used before more tag. Manual excerpts have some advantages over automatic excerpts and the biggest advantage is that here you get full control of explaining what is your post is all about and that becomes very useful specially in the search results.
Most WordPres themes provides you functionality of manual excerpts. By default Manual Excerpt meta box is hidden from Add New & Edit post pages. So if you want to give manual excerpts to your blog posts then first visit your admin area Dashboard -> Posts -> Add New page.
Now second step is to click ‘Screen Options’ present in the top right corner, just below the Howdy text. Now tick ‘Excerpt’ checkbox present in ‘Show on screen’ section.
That’s all. Close ‘Screen Options’ and scroll down, you will be seeing a new meta box for the excerpt is added. Use this metabox for writing manual excerpts for your posts.