here's the round-up I trust. First thing I do is check the big official storefronts:
MANGA Plus (Shueisha), Kodansha's
K MANGA, VIZ Media, BookWalker, ComiXology/Kindle, and the major English publishers' shops like Yen Press or Seven Seas. If a manga is officially licensed in English it’ll usually show up on one of those platforms, or as a Kindle/ComiXology listing. Crunchyroll Manga and local digital libraries (OverDrive/Libby, Hoopla) are also worth a look — sometimes publishers partner with them for digital lending.
If you can’t find it on those sites, the next move is to check the creator’s official pages: Twitter, Pixiv, an official website, or a Patreon. A surprising number of creators self-publish or sell digital/physical copies directly via Booth.pm or DLsite, especially if the work is indie or doujinshi-style. Some titles get English translations through publishers later, so keeping an eye on the author or publisher account helps. For older or out-of-print works, secondhand marketplaces (Mandarake, eBay) or specialty shops can be the only legal route to own a physical copy.
My general rule is: if it’s not on a recognized platform or the creator’s own shop, be patient and resist sketchy scan sites. Supporting official channels helps the creator keep making more stuff I love — I’d rather buy it properly than scramble for a dubious copy, and I’m always rooting for a proper English release.