You can simply create a WordPress Post. This post will tell you all basic details about the Creating WordPress Post.
Just go to Admin panel of your wordpress site. Then click on Posts and Click on Add new option on the left side of the page.
Enter Title And Content Of Your Article or Post
Click On Publish Button To publish It
Here (Right side of the post) you can see many options for publishing post. You can publish it by clicking the publish button or you can save the post by clicking Save Draft Button. You can also Preview the post by clicking the Preview button.