Roll20 is a tabletop emulator designed to work for most RPGs. The virtual tabletop can take a little time to learn, but it is powerful. A really great tool for playing long-distance games, or if you would rather take care of all of your sheets, rolls, and campaign management online.
You can find the official blank Dungeons and Dragons character sheets here. There are also several pre-generated characters you can use. They’re great if it’s your first time and you’re not sure how to begin, or if you just want to get started right away.