I never thought to do this, it sounds like a great idea really XD I mean it works for Youtubers, lol.
I usually put them in the description of the episode. And it's more often me being meta about the story or something or joking them it is those questions.
I usually just put a single question at the end that kind of summarises the themes or ideas focused on in that chapter. I'm hoping it adds a layer of mystery or intrigue to the story. I kind of wished the description was shown before the story but eh, it doesn't bother me too much.
So I’m actually reading through a series (that I will not name) that has a copy/paste like/sub/comment message along with patreon and whatever else links and it ends up being long and messy... and I’m not a fan. Especially since they will, occasionally, post some little note specific to that episode and it’s hard to see them through the copy/paste clutter.
On the flip side of that, it makes me just a tiny bit sad when there is zero authors note 
I put at least a little personal commentary at the bottom of each of my episodes. I mean, sometimes it’s a complete paragraph of me rambling and sometimes it’s 3 words, but I try to put a tiny something to make it more personal. I figure that people will like/comment/sub if they want to and me posting a reminder after each episode probably isn’t going to sway them. That’s just my take on it, though. Everyone is going to find a different version that works for them and their readers.
I use episode descriptions for my notes mostly, particularly in my webnovel. The only time I'll put a note in the body of the episode is if it's a content warning or a warning that the next episode will be mature.
For my comics, from time to time I will add this little banner after the pages as a friendly reminder. But I'll add all the links in the episode description.
The notes I put in my episode descriptions range from my own commentary to announcements.
I try to ask questions regarding the story, like if the readers would agree with the descision of the characters or what they would do differently.
I never ask for subs or votes in there
oh yes, I like the little notes @rifftiff leaves at the end of her comic regarding Korean culture.
Uh...no. My god no. I've seen it in fanfictions a lot but uh...no. I leave anything I want to say in the chapter notes and such but never in the chapter itself...
The notes I put at the end are for explanation of certain things, because I can't have underlines and there are also facts about Slavic mythology that the people who are reading might not know.
Every chapter has a note at the end. Usually if I don’t think something makes sense like if there’s a mini timeskip that I transition with, I just add it into the “summary” Thing for the chapter.
I hate leaving a chapter without notes, even if they're just little ones. Might try to be a bit more engaging with the comments or leave little lore snippets if they fit 
I usually include notes at the end of my pages when something is going on that might need more explaining. Like given my comic has a lot of reference to stuff from the 80's, 90's, and 2000's, not everyone might get what the page is referring to, and so I include descriptions and links a lot.
To be honest, and I am talking as a reader here, it depends what kind of "note" you put there.
Putting something like a footnote at the end of a chapter, where you have some fun with your characters, like breaking the fourth wall, or giving a little sneak peak to the upcoming chapter or just something that goes on in the world, I will say that is fun and a little bonus for the reader
But putting under every chapter something like "Please Subscribe" or "Please Share" and so on, I dont know I always feel like the author is just too desperate - I mean watch some YouTube videos where the creators always start with 2 Minutes asking for donations and follows, then again in the video and at the end - it just gets annoying at some point 
Now as I said, I say this from the view of a reader - as a writer I can understand that you want to have readers - heck I will admit, it would be nice to have readers for my own story, but i only see this 0 there 
) - and I also have it in my YouTube videos, but only on a card on the end (except two videos) because I just don´t want to give the viewer the feel of me just wanting to do these videos/writings/etc to become famous and not because I have fun doing them.
But I would always put something in the description of the chapter
Coming from a reader's perspective, I wouldn't like notes in the body of the chapter. I think it looks really unprofessional and ruins the immersion. If the notes are left in the actual author note section where it is separated from the body then I support that as a reader and an author. I always leave questions concerning what happened in the episode since it definitely helps with engagement.
I put anything I need to say in the actual notes, I like to keep the body for the actual story. I don’t like seeing comments underneath the story either, save them for your notes or even in the comments section
I never thought about asking questions in the author's note until now... I think I'll start doing that
I don't know what I'm doing at all in the author's notes, but I try to put something in there. Usually a clarification or a bit of background info that didn't make it into the story. No idea yet if this is something people like or just me feeling like I need to put something there!
I love reading short notes from the authors in the chapter descriptions - it's fun and sort of invites me to interact with them a little more. Personally, I always add a "Thanks for reading" with a short comment or fun fact specific to said chapter. Not only to cause another opportunity for interaction, but mainly because I like sharing my thoughts with others or some random facts concerning the writing process of the chapters. It doesn't have to be long, but it's at least something and can't hurt.