You want to make a blog post sticky in WordPress when you want that particular blog post to remain at the top position of your blog home page or main page. This way it remains accessible to all the traffic that comes to your blog homepage for a long time.
Normally what happens is, the blog posts on your homepage are arranged in a chronological order, with the latest blog post appearing at the top, and the blog post before it underneath, and so on. What it means is, the moment you publish your new post, the existing post moves downwards. If you have set your blog to publish 10 latest blog posts on your homepage the moment you publish the 11th blog post the 10th blog post that was once at the top, vanishes from the first page. When you want a particular blog post to be sticky, you not only want it to remain on the first page for as long as you want, but you also want it to appear at the top of all the blog posts no matter in what order the blog posts are organized.
Previously you needed a plug-in to make a blog post sticky, but no longer. All you have to do is, create a new blog post, or open an existing blog post. Then go to the “Publish” section (in case you are trying to make an existing blog post sticky, the “Publish” button will appear as “Update”) and look out for “Visibility”:
Click on “Edit” and another set of options opens up:
Here you can see the “Stick this post to the front page” checkbox. In case you want this post to be sticky, check this box and then click “OK”
That’s it. Once you publish the blog post, it will remain there at the top unless you uncheck this checkbox and save the blog post again.