To read Japanese manga effectively, it's good to have a basic understanding of Japanese grammar and culture. Familiarize yourself with common manga genres and their tropes. And don't rush, take your time to enjoy the art and story.
Manga is Japanese. It has developed a huge fan base worldwide for its diverse characters, complex plots, and artistic expressions that are specific to Japanese creative traditions. In contrast, Chinese comics have their own names and styles that set them apart.
Well, there are several places. Some people recommend subscription-based services like BookLive or Kindle Unlimited Japan. Also, some manga authors have their own official websites where you might find their works in Japanese. Just make sure to have a reliable internet connection and a way to make payments if needed.