I want to upload a web comic series but I'm not sure how the format would work since Itch.io was made mostly for uploading games.
Itch has an area for comics, normally they are in PDF and can be downloaded, if you want to view them via the web, you need to place the images or the PDF within HTML5 code, if you search on Google there are a couple of "engines" that could help you.
https://itch.io/comics
Itch sure has a place to upload pdfs of comics, but I would say that other plattforms that specialize on webcomics are still better and more frequented. - But this is only my personal viewpoint and that might not be right. I can only say that I know quite a bunch of people reading webcomics, but noone seems to read them here. :-) --- If you tried it, do not hesitate to let me know about your experiences. :-)
Itch can host digital files. That can be comics in the usual comic book reader formats. PDF is not especially suited for this, but many use it anyway. There are comic book readers that use more suited formats. But those are usually just zip files with a special file ending and conventions how to name the files inside the archive.
Using Itch as a online display for a comic series is tricky. Itch offers not really much help there. Just like you could upload a movie here, but there is no video player, unlike a specialized site like Youtube.
Webcomic series are ususally hosted on the site of the developer. Itch is not suited for frequent updates of comic strips. Hosting archived versions of a series is more suited to Itch.