Using Logic Apps, workflows can be defined that consist of a sequence of API calls and the corresponding progressive processing of data, i.e., returns from an API can be used as call parameters for subsequent APIs. This enables the implementation of business processes that can include custom application logic (using independently developed APIs) and logic from various backend systems (via pre-built connectors loaded from the Marketplace and appropriately configured).
Azure Logic Apps - Getting Started
Episode 176: Logic Apps with Stephen Siciliano
Build cloud-first Enterprise integration solutions with Logic Apps
Automate Business Process With Logic Apps (Deep Dive)
Integrating your Systems with Logic Apps