I can't speak to other countries, but it seems to be the norm in the US. APA (American Psychological Association) style calls for capitalization of major words

I can't speak to other countries, but it seems to be the norm in the US. APA (American Psychological Association) style calls for capitalization of major words in titles, and that seems to be the most commonly assigned style for college students. The other two common styles I've seen referenced in the US, MLA (Modern Language Association) and Chicago Manual of Style (usually just referred to as Chicago style) both also call for similar capitalization. I don't know of any standards that call for normal sentence capitalization for titles, so I assume they must be in-house standards or some standard that is not common in my domain.