How do I show a list of nodes referenced by a field? I created two content types: News Agency and News.
The News content type has the Headline, Title, Body, and News agency name (a reference to a News Agency node) fields. The News agency content type has the News agency name and Publisher fields.

I need to show the news related to particular news agency. I am trying to set a relationship, but it still doesn't show result.
The "Entity reference" field has a few options about how to display the referenced entities (Label, entire node, Node ID). 

But you're referencing News agencies from News nodes, not the other way around. So you're able to choose how News agencies are listed on News pages through the "Manage display" settings in Content type. 

If you want to list nodes on the News agency pages you need to use Views to create "backwards" Relationship: 


Create Views listing News, Block display
Add a Contextual filter for the Entity reference field relating to the News agency and configure it
When the filter value is NOT available
Provide default value
Content ID from URL
When the filter value IS available or a default is provided
Specify validation criteria
Content
Related? News agency  

Test the configuration by entering one of your News Agency NIDs into the Views Preview field. You should see News nodes that relate to that agency in the view results. 
If everything is working as expected place the Block into a region in your theme and configure it to only appear on the News Agency pages, and configure the filter option for the reference. 


Now when you visit News Agency pages you'll see a list of all News that relate to that agency.