The general rules for the use of upper and lower case letters (capitalization) apply to sentences, proper names, and headings and titles.
1.Proper Nouns and Trade Names
e.g., Mariam Mohammed, Hamad Medical Corporation, The University of Calgary in Qatar
2.Nouns Followed by Numbers or Letters
e.g., Table 1, Case Study 3.
3.The First Word of a Sentence
e.g., She works in pediatrics.
4.First Word After a Colon Only If the Words After the Colon Are a Complete Sentence
5. Second Word in a hyphenated word where the first word is capitalized
e.g., T-Test, Pre-Registration
The rules for APA style documents are divided into the categories of Sentence Case and Title Case.
Capitalization for the first word as well (as well as any proper nouns) is used for the following:
1.Article titles (references list)
2.Book titles (references list)
3. Webpage titles (references list)
4.Newspaper are internet document title (references list)
5.First word after a colon in article titles (references list)
6. Table column headings, entries, and notes
7. Figure notes
Capitalization for each major word is required for the following. A major word is one that is four (4) letters or more. Two to three letter words such as prepositions, conjunctions, and articles are not capitalized unless they follow a colon.
1.Journal or Periodical titles
2.All titles of books, articles, and other documents that are given in the body of your text
3.Level 1, Level 2, Level 3, Level 4, and Level 5 headings in your paper
4. Title of your paper
5. Table and Figure titles
See your APA style manual, pp. 165-170 ("Capitalization")