The ever-increasing complexity of networks and services advocates for the introduction of automation techniques to facilitate the design, the delivery, and the operation of such networks and services. The emergence of both network function virtualization (NFV) and software-defined networks (SDN) enable network flexibility and adaptability which open the door to on-demand services requiring automation. In aim of holding the increasing number of customized services and the evolved capabilities of public networks, the open network automation platform (ONAP), which is in open source, particularly addresses automation techniques while enabling dynamic orchestration, optimal resource allocation capabilities, and end-to-end service lifecycle management. This chapter addresses the key ONAP features that can be used by industrials and operators to automatically manage and orchestrate a wide set of services ranging from elementary network functions (e.g., firewalls) to more complex services (e.g., 5G network slices).