In administrative theory, what are doctrine of unity of objective, service concept, and process of delegation?
Henri Fayol (1841–1925) pioneered organization theory. His ideas have formed the bedrock of later organization and administrative theories. His foundational ideas were based on finding the "most rational" organization within a firm assumed to be rational itself. The most rational organization stemmed from coordination of tasks and division of labor. Fayol posited that rational and efficient organization of firms were founded upon "‘unity, continuity, flexibility, precision, command and control" (General and Industrial Management, Dictionary of Sociology).
Fayol's doctrine of "unity of objective" is more correctly as "unity of direction." This doctrine means that individuals engaged in similar tasks within an firm must pursue a common, or united, objective that fulfills the overall plan governing tasks and division of labor.
It is unclear what "service concept" you refer to, but Fayol's principle (or doctrine) of remuneration states that workers must be paid a fair wage for the service(s) they perform. Additionally, the principle of esprit de corps relates to unified and harmony service to the firm as a result of the promotion of team spirit within the company.
Delegation relates to Fayol's fundamental concept of division of labor. Fayol never uses the term "delegation," but the concept of delegation, i.e., to commit powers and tasks to another person who is qualified to carry them out, is embodied in his principle of division of labor. This principle states that division of labor is the assignment of tasks to a group of employees in order to increase production efficiency. Fayol brought attention to the fact that for every task, there are any number of processes that must occur for the task to be complete.