How to change the number of posts on the blog page
You can customise the number of posts that are displayed on the blog page.
To do this, hover over Settings in the left-hand menu of WordPress and click Reading.
Once on the Reading Settings page, you should see the Blog pages show at most option.
The number here dictates how many posts will be shown on the blog page. You can change this to whatever you like.
When you’re finished, click Save Changes at the bottom of the page.