Pages vs Posts
Before telling you how to create pages and posts, it's worth pointing out the differences between pages and posts. Essentially there is no difference and both are created in a similar manner, but there are conventions that differentiate between the two.
Posts normally belong to a person's dated blog, and they're usually presented in date order with the latest post at the top.
All this is only convention, though, and you can use pages and posts as you wish. Some WordPress sites are less like blogs (or the blog is only a small part of it) and consist of mainly static pages. Other sites are largely blogs and will consis mainly of posts.
Creating a Page
To create a page, hover over the Pages item in the WordPress admin area to bring up the floating menu, then click on Add New.
Creating a Post
To create a page, hover over the Posts item in the WordPress admin area to bring up the floating menu, then click on Add New.
See the next section for information about creating content in a page or post in the block editor.