When WordPress was first developed, it was primarily used for blogs. Therefore, there was only one kind of content that could be produced: a post.
Today, WordPress allows you to create several different kinds of content beyond just simple posts. For example, pages are considered a type of post and usually are reserved for static, (semi)permanent content rather than dynamic content in the form of a blog post.
“Post types” allows you to sort and organize your content more efficiently without referring to any difference per se in content. In other words, you create each post type the same way. Using the different post types is for when you or the WordPress system wants to later retrieve and/or display the information.
WordPress comes with several built-in post types:
Post – The standard (blog) post.
Page – A static, semi-permanent post that can be organized in nested hierarchies.
Attachment – Contains information about an uploaded media file.
Revision – Previous versions of a published post.
Navigation Menu – Information about a single item in the WordPress navigation menu system.
Custom CSS – A post used to store custom CSS information.
Changesets – A post used to store previously used settings for your website.
The last five post types may be created automatically when you change information or modify the settings for your WordPress site. The information in these specific post types is stored as a post to make it easier to retrieve and modify, but you don’t need to worry about understanding or using these if you’re a WordPress beginner.
Note: You can also create your own post types. Some themes also come with their own custom post types.
The availability of different post types depends on which version of WordPress you are using.