ISO 20000 is the international standard for IT Service Management (ITSM), published by ISO (the International Organization for Standardization), and ICE (the International Electoral Commission). To become an international standard, ISO 20000 had to be agreed upon by a majority of member countries, which means it is accepted by a majority of countries worldwide.
The standard describes a set of management processes designed to help you deliver more effective IT services (both to those within your business and to your customers). ISO 20000 gives you the methodology and the framework to help you manage your ITSM, while allowing you to prove that your company follows best practices; in turn, these best practices will help to improve your delievery of IT services. And ISO 20000 is applicable to any company size and any industry.
ISO 20000-1:2018 is the formal specification for IT Service Management. It clearly defines all the requirements you need to deliver managed IT services of an acceptable quality for your customers. It includes service management system (SMS) requirements.