The Post content type comes with Backdrop CMS out of the box. It's good for articles and blog posts. If the default version of the Post content type does not suite your needs, you can delete it and create a new version from scratch or modify the existing version.
At the time of this writing, we are not using the Post content type for our Farmers Market site, but we have kept the content type active in case we decide to add a blog later.
The Post content type comes with four fields by default: