Step 1: Understand staffing.
Staffing refers to the process of hiring, training, and placing individuals in appropriate positions within an organization.
Step 2: Evaluate the options.
- Staffing involves appointing the right individuals for the right roles based on the organization's needs.
- While planning, controlling, and directing are important functions of management, they do not encompass the entire staffing process.
Step 3: Conclude.
Staffing specifically focuses on appointing individuals to the required positions in an organization.
Final Answer:
\[
\boxed{\text{To appoint the persons on work}}
\]