From https://www.presidentialserviceawards.gov, they use the expression "The President's Volunteer Service Award (PVSA) is the premier volunteer awards program".
Why were capital letters used, instead of simply "The president's volunteer service award"? Is it to make acronym or is there any other rule for this?
It is the official name of the awards program, thus it is a proper noun, so the words are capitalized.
You can see this explained here in the section titled "Organizations, Groups, and Other Entities":
To refer to "the town’s chamber of commerce," as we do in sentence 4 of the opening exercise, is to use a generic label. On the other hand, to refer to "the Buckville Chamber of Commerce" is to call the organization by its individual name, its pr oper name. Likewise, to say "the Ravenwood Historical Society" is to use the official name of the particular organization. To say "the historical society in the Ravenwood community" is to speak of the society in the generic sense. The former is capitalized; the latter, lowercased.
We capitalize the formal names of specific entities because they are proper nouns:
- the Society for the Advancement of Grammatically Correct E-Mail Communications
- the Grand Strand Area Transportation Council
- the Chrysler Corporation
- the Consortium for Language Learning
- the Los Angeles School for the Deaf
- the National Assistive Technology Advisory Board :
Note that these formal names follow the guidelines for capitalization of titles, though there's no one set of "rules". Some examples of title capitalization can be seen here.
They are capitalized because The President's Volunteer Service Award is Proper Name.
That's all. No other special reason.
