How to Add the WordPress RSS Widget
The WordPress RSS widget allows you to pull headlines through aggregation from almost any Really Simple Syndication (RSS) feed, including recent headlines from your other WordPress blogs or sites and headlines from news sites or other sources that offer RSS feeds.
From the WordPress Dashboard, choose Appearance→Widgets.
Drag and drop the RSS widget from the Available Widgets section to the desired widget area on the right.
Open the RSS widget's drop-down list to display the options you can configure for the RSS widget.
In the Enter the RSS Feed URL Here text box, type the RSS URL of the blog (or site) you want to add.
You can usually find the RSS feed URL of a blog (or a site) listed in its sidebar.
(Optional) Type the title of the RSS widget.
This title appears in your site above the links from the site.
Select the number of items (from 1 to 20) from the RSS feed to display on your site.
(Optional) Select the following options as desired:
Display Item Content: Select this check box if you want WordPress to also display the content of the feed (usually, the content of the post from the feed URL). If you want to display only the title, leave this check box deselected.
Display Item Author If Available: Select this option if you want to display the author’s name along with the item's title.
Display Item Date: Select this option if you want to display the date the item was published, along with the item title.
Click the Save button.
WordPress saves all the options you’ve just set and reloads the Widgets page with your RSS widget intact.