All headers should be capitalized text using the common rule for title capitalization: Conjunctions and prepositions are NOT capitalized, but everything else is capitalized PLUS the last word in any title is capitalized.
Here is a good example:
Here is another example using “where” as a conjunction, and therefore is NOT capitalized.
Honoring Colleges where Community Service and Civic Engagement Are Valued
And a title with an ending preposition, using the last word capitalization rule:
Is This All You Can Think Of?