Is there a required report that companies must submit to share upcoming dividend payments? I looked on sec.gov, but couldn't find documents relating to what I'm looking for. I found this PDF that suggests it should be filed, I'm just unsure of what I'm actually looking for, I guess.
Public companies must abide by SEC rules of fairness and equity in dividend announcements. SEC requires public companies to announce material information publicly in a way that no one can take advantage by trading on non-public information at the expense of other market participants.
Dividends are published in a press release by the company to all investors through the company's website and to the SEC through SEC website in form 8-k. Dividend announcement usually happens at the same time and in the same press release of the company's earnings.
Form 8-k is not exclusive to dividend announcements. Company's file form 8-k to communicate material information to regulators and investors
You can search for all US companies forms on https://www.sec.gov/edgar/searchedgar/companysearch.html
According to this, companies will send out a financial report to investors announcing dividend payouts.