There are three types of post formats you can make on your site: Standard, Gallery, Video. Go to Dashboard >> Posts >> Add New and look for the Format module on the right.

Post Formats
Post Formats

1. Standard

This is default styling for the WordPress theme. Simply add new post or edit post and select post format as “Standard” .

Standard Post Format
Standard Post Format

This is how it should look like at front-end:

standard post formay
Front-end Appearance

2. Gallery

This format will show a thumbnail image from your posts, as well as an excerpt of the gallery.

To have this post format, you need to add gallery for the post by clicking on “Add Media” >> Create A Gallery >> Press ” Insert Gallery” button in order to insert the gallery into the post.

Insert Gallery Into Post
Insert Gallery Into Post

After clicking on Add Media button, you will see an window shown. To have the images gallery, you choose Create Gallery, then select the images you want to display.

premium_wordpress_themes_dw_fixel_create_gallery
Create Gallery

After that, select post format as Gallery.

Select Post Format As Gallery
Select Post Format As Gallery

This is how it will look like at the front-end:

Gallery Post
Gallery Post

3. Video

This post format will highlight your videos. Just go to Posts >> Add New/ Edit , then simply paste a video link into the post and select Post Format as “Video”.

Note: You should set featured image for the video posts in order that it will display properly at front-end.
set featured image
Set Featured Image

Here is front-end appearance:

video post
Video Post