One option is to look on Crunchyroll. They often have a wide range of manga, including 86. Sometimes you might need to have a subscription to access the full content.
You can start by creating an account on Crunchyroll. Then, navigate to the manga section and look for the titles you want to read. Some may be available for free, while others might require a subscription.
Well, it's not strictly necessary. The anime might give you a decent overview. But the manga often has more details and might offer a different perspective.