For articles, be sure to enter the database you found your article in the Archive field - it will then be included in the correct place in your bibliography.
If your article citation does not present in sentence case, you can right-click on the title in your Zotero library and change it in the library from title case to sentence case (you will need to manually capitalize the first letter of any proper nouns as per APA style). Then when you insert it in your document it will be correct.
Using the Drag and Drop Citation Method (Any word processing program, email, blog posts, virtually any electronic document):
See the Annotated Bibliographies tab of this guide
Using the Microsoft Word (Windows and Mac) / Libre Office Plug-in:
Official Zotero documentation