One option could be to check out official manga subscription services. Some well-known ones are Shonen Jump and Comixology. These platforms might have MHA manga for you to enjoy. Also, some libraries might offer digital access to manga, so that's worth looking into as well.
There are several places to read MHA manga. Some popular options are subscription-based manga services or the official website of the publisher. Just make sure to choose legal sources to support the creators.
The best places to get MHA manga are large online marketplaces like eBay or specialized manga websites. You might also find it at conventions or from second-hand bookstores.