Program services are activities that are conducted by the organization, which serves the organization's exempt purpose. The organization's top three program services in terms of the highest revenue should be listed in a detailed manner as the program service accomplishments.
The organization can attach schedule O if they want to list more than three program services. The program services should be explained in detail in the attached Schedule, and the revenue and expenses of the programs should also be listed in the Line 4d of Part III in Form 990.
The program services which were conducted in the previous year and hasn't been reported to the IRS should also be listed and explained in the Schedule O attached.