When you use APA 7th edition
APA is the style of the American Psychological Association, and the 7th edition from 2020 is what nearly every psychology, education, nursing, business and social science course asks for today. If your assignment brief just says APA without a number, it almost certainly means the 7th edition.
The style runs on an author and date system. Every source gets a reference list entry with four blocks in a fixed order: who wrote it, when, what it is called, and where it came from. Once you see those four blocks, most of the formatting rules start to make sense instead of feeling random.
The tool above already knows the rules. It pulls real metadata from Crossref for DOIs and Open Library for ISBNs, so journal articles and books come out clean. For ordinary web pages it reads the page metadata, which is usually right but always worth a quick check against the page itself.
The formats, with real examples
Paste your source into the tool above and it fills these in for you. If you would rather see the pattern, here is exactly what each one looks like.
In-text citations
Two authors: (Smith & Lee, 2023). Three or more authors: (Smith et al., 2023) from the very first citation. No author: use the first words of the title in quotation marks, like ("Flu Symptoms," 2023).