The service sector plays a crucial role in modern economic development. In the initial stages of economic development, a larger proportion of people worked in the primary sector. However, in a developed economy, the majority of workers get employment in tertiary activity, while a moderate proportion is employed in the secondary sector.

Today, most people are service workers. Services are provided in all societies, but in more developed countries, a higher percentage of workers is employed in providing services compared to less developed countries. This trend shows the growing significance of the service sector with economic progress.

Services occur at many different levels. Some are geared to industry, some to people, and some to both, such as transport systems. Low-order services like grocery shops and laundries are more common than high-order services like those of accountants, consultants, and physicians.

Personal services facilitate people's work in daily life. Workers migrate from rural areas seeking employment and work as housekeepers, cooks, and gardeners. This segment is generally unorganised.

Services are provided to consumers who can afford to pay. Workers perform either physical labour like gardeners and launderers, or mental labour like teachers, lawyers, and physicians.