What's the difference between sentence case and title case?
Sentence case refers to capitalizing the first word, first word of a subtitle, and all proper nouns, and usually is applied to formatting the title of a resource in a reference. For example, in APA Style, journal article titles and book titles should be presented in sentence case within references.
Title case involves capitalizing all major words. For example, in APA Style, the title of an essay that appears at the top of the first page of text (see page 2 of the Sample One-Experiment Essay) and journal titles in references are in title case.
For more information, please see "Title Case and Sentence Case Capitalization in APA Style" from the APA Style Blog. For a list of which resource titles should be in sentence versus title case in references, please see #6 in the "APA Style References Checklist".