APA has a large table of examples for what to do when you're missing author, title, date, or some combo of the above.
Is it missing or is it in a weird spot? Look at the top and bottom of the article/page, at the website header and footer; look for an About page; consider the url and what you can chop off to get back to the homepage (especially if it's a .edu link).
In short,
Missing Author
Your citation will start with the source title. The date will come after the title instead of coming after an author.
Two years on, the Kuiper Belt is in sight. (2017, September 16). The Economist. https://www.economist.com/science-and-technology/2017/09/16/two-years-on-the-kuiper-belt-is-in-sight
Parenthetical citation: ("Two Years," 2017)
*Yes, with capital letters and quote marks, per APA 7th ed., 8.14.
Missing Date
Substitute "n.d." (as in, "no date") wherever the date would appear, both in your reference and in-text citations.
Implicit bias. (n.d.). Perception Institute. https://perception.org/research/implicit-bias/
Parenthetical citation: (Implicit Bias, n.d.).
*Yes, with a capital B in Bias for the parenthetical. Not a typo. APA 8.14 again.
Missing Title
Write a brief description of the source inside square brackets; the period goes outside the closing bracket. (This probably comes up the most with images you find online, which often aren't formally titled if they aren't Art.)
Landacre, P. (1966). [Illustration of paper birch trees]. In D. C. Peattie, A Natural History of Trees of Eastern and Central North America (2nd ed., 164). Houghton Mifflin.
Parenthetical citation: (Landacre, 1966, p. 164).
