Honestly, finding truly free and legal digital comic downloads can be tough. Some sites claim to offer them, but often they're either not legitimate or have poor quality. Your best bet might be to look for promotions or free samples on official comic platforms.
It depends. While it might seem convenient, it's usually not a good thing. It's illegal and unfair to the comic creators who put in a lot of effort and deserve to be compensated for their work.
You can use dedicated comic reading apps available on the App Store. Some popular ones are Comixology and Marvel Unlimited. Just download the app, search for the comics you want, and start reading.