When making an educational video, does citation need to be in the video itself? I can't seem to find any information on this. If a person is making an essay, or a research paper there are specific rules about citation. Such as, if a specific fact is used in a paraphrased way, a citation has to be listed for where those facts came from. For video making, I haven't seen any information about it. I've found how to cite a video in a paper, but not how to cite a paper in a video or if it's even necessary. Since I'd be making a Youtube video, I could have my sources in the description, maybe even at the end of the video itself, but would I have to cite things as I'm saying them? I don't think so, but I'm also not sure either. To be honest, I've seen educational Youtube videos that don't do this, but a lot of those videos don't even cite their sources either.
The big disadvantage of citations that are part of the video itself is that they can't easily be a link, or even copy-pasted into a search engine like a text citation. So if it's a URL, the viewer will have to pause the video, and type the URL manually. You could use YouTubes "cards" function to add links as pop-up interactive overlays, but I think you are limited to 5 links per video.

I would put my citations in the description, and in case the video gets embedded somewhere else, give them at the end of the video as well, perhaps with a link to a page where they could be found.

There is no set convention that I know of, unlike citations in papers or books. There is a podcast that I listen to that does give citations, but they just tell you how many at the end and send you to their website to read the transcript to find them. I don't think most viewers are expecting them, except for the implicit citation you give when you say something like "in a 2019 study by Dr Stib, it was noted that…" when citing other's research.