There are 4 different types of Post style available in Freesia Ghost theme.

If you the following tag in your post ( video, link, quote ) then it will display different post card style in your website.

Video

Just use the tag Video, then it will display the video post in the following design.

Link

Just use the tag Link, then it will display the link post in the following design.

Quote

Just use the tag Quote, then it will display the quote post in the following design.

Image

Just upload a featured image in your post, it will display the standard post in the following design.