Human beings engage in various economic activities to earn their livelihood. These activities are broadly classified into three categories:

All three aim at earning income, but they differ in nature, purpose, and method of working
Business
An economic activity in which individuals or organizations are engaged in the production, purchase, sale, or exchange of goods and services with the main objective of earning profit. It involves regular dealings and satisfaction of human wants by providing goods and services.
A business is not a one-time activity; it is a continuous process that includes production, distribution, marketing, and sales. It also involves risk and uncertainty because profit is not fixed and depends on market conditions such as demand, competition, and cost of production
Profession
An occupation that requires specialized knowledge, training, education, and skill, which is applied in providing expert services to society. A person practicing a profession is called a professional.
Professionals must complete formal qualifications and are usually governed by a professional body that sets rules and ethical standards. The main aim of a profession is to provide service to society, although professionals also earn income in the form of fees motive, reward or return, etc.
Employment
An economic activity in which a person works for another individual or organization under a formal or informal contract and receives a fixed payment in return, such as salary or wages.
In employment, the employee works under the control and supervision of the employer and must follow instructions. The income is fixed and regular, and the risk is very low compared to business. Employment provides job security, stability, and fixed working hours.