Post Display Formats
Whether you are displaying your latest blog posts on the front page or you have a page to show your blog posts – the blog feed display is controlled via the options under Appearance > Customize > Blog Feed, the "Post Display Format".
Image and Excerpt: This setting shows the excerpt of the post along with the featured image.
Click here for a demo of this format.
Image and Full Content: Choosing this will show full content of the post along with the featured image (thumbnail). If you use the “more tag” (see https://en.support.wordpress.com/more-tag/) you can control how much content is visible in the blog feed and the user can click “more” to view the complete post.
Click here for a demo of this format.