In print, web content and on digital projects, use sentence style, meaning that the first word of a headline should be capitalized, but the other words are not capitalized unless those words are proper nouns.
In general:
Copy headlines or link text = This is sentence case.
Label or button = This is sentence case.
Numbers in headlines must always be in numerical form because web writing and print headlines call for concise headlines that maximize character counts. (In body copy, spell out numbers zero through nine.)
The percent symbol, not the spelled-out word, should be used in headlines and body copy, for the same reason numbers are used in numerical form.