This is a very common question. Posts and Pages can look and act so similarly. You may have noticed in the admin area they look very much the same. Both have a title, content area, featured image, etc. The differences are subtle, but they’re there. Let’s take a look.
The word “blog” is actually short for “web log”; basically a journal on the web. So then each post is an entry in a journal. Because of this, each Post is tied to a point in time, the time and date on which it was published.
Then once each Post is published on a certain date, all Posts are presented in chronological order on the web site. WordPress creates archive pages for them, and prints “Next” and “Previous” buttons, so you know in what order to read.
So Posts are intended to be a chronological series of entries, related to each other by time.
Pages on the other hand are intended to stand alone. If they’re related to other Pages, it’s by content, with an arbitrary hierarchy of importance.
A great example of a Page would be a page about a Ford Mustang. It has a title, description, maybe some pictures. But once the page is done, it’s simply done. You don’t make another one tomorrow.
Putting It Together
You might have a site that is about your Ford Mustang and the experiences you have with it. The About Page would talk about when you bought it, why you like it, and have some pictures. But then the blog area of your site could be a series of Posts about trips you take with it.
Say you drive it from Chicago to San Francisco. Each day you do a Post, and categorize it as “Road Trips” with a sub-category of “Chicago to San Francisco, 2017”.
Then you have it shipped to Hawaii, and you do a series of Posts on what it’s like to ship a car to Hawaii.
When you get there, you do another series of Posts about driving all the way around The Big Island, in the “Road Trips” category, with a sub-category of “Hawai’i, The Big Island, 2017”.
After a few years you have a rich site full of adventure and pictures. You start taking advertising and you have a full blown travel blog.
Meanwhile, your Page about your Mustang really hasn’t needed to change much. You might do an update when you get the engine rebuilt, or get the flames painted on it, but for the most part your Page just sits there.
As you can see above, Posts are for ongoing content, related to itself by date and in other ways as well, like category. Pages are single items that stand alone, and usually don’t need to be changed.
The road trip thing could really happen; many people do it. You should try it.