Logic App can be created by selecting the Web + Mobile option in the search pane and by then selecting the Logic App option.

Once you open Logic App, you can see the Logic App Designer, pane as shown in this screenshot:

You can select any predefined templates, or create a blank app. Predefined templates provide a quick way to create a Logic App to provide a certain functionality, and with a few simple wizard steps, the app becomes ready. These templates include sending an e-mail when the SharePoint list item is modified, delivering an e-mail on new tweets added to your Twitter account, and so on.

With the Blank LogicApp option, we have a choice to select the connector from the available connectors, such as using Managed Microsoft API, or APIs from App Services in the same region, or using API Management available in the user's subscriptions. We can compose Logic App using designer and edit the workflow through code view using the Logic App definition language. Let's take the example of a simple workflow that posts a tweet on a configured Twitter account whenever new blogpost is published on WordPress. To achieve this scenario, we first select the WordPress (when a post is created) activity from Microsoft Managed API, and provide the WordPress credentials. We can also set the interval at which Logic Apps should check for any new post published on a WordPress site:

Next, we can add an action or loop activity, and choose Twitter connector to post a tweet on the configured account:

When adding a new step, you can choose from adding an action, a condition, a for loop, do until loop, or scope:

So with Logic Apps, you can quickly create workflows that run under Azure App Service on the Azure portal, and are easily configurable with a provision of a number of available connectors to choose from.