ISO Standards are internationally agreed upon by experts. Simply, think of the formula for doing something most finely. Standards are the best practices by the experts in their field matter and they know the requirement of the organization they represent. People such as trade associations, regulators or users, buyers, customers, sellers, manufacturers, service providers.
For example,
Quality Management Standards to perform an activity more efficiently hence reduce failures.
Environment Management Standards to help in environmental impacts reduction, waste reduction and to be further sustainable.
Health and safety standards to help accidents reduction in the workplace.
Energy management standards to help energy consumption reduction.
Food safety standards to help food prevention from being contaminated.
IT security standards to help provide security to sensitive information.