1) Renpy.
2) If you're talking about the live2d animations like in this game, the image(s) are first created on any digital art program like photoshop or clipstudio before animating them in animation programs like adobe animate.
3) If you're new in the visual novel dev scene I suggest you read up on renpy's documentation or watch online tutorials on it, as it's very beginner friendly and pretty much widely used even with more popular titles like DDLC. Experiment, see how the program feels, make a dummy game. It can even be a joke game. It could serve to get you accustomed to the program's functioning.
Drawing and animating are a completely separate matter I can't be of much help with that. If you intend to make all your assets yourself online tutorials can get you started on that but it's a steep hill to climb as a beginner and takes a lot of time to master. There are many visual novel assets online that are free to use, pretty sure there are some reddit/steam threads with a list of links for those if you search them up. Otherwise if you have the funds you may hire or commission someone experienced to help you with the art and animation (fiverr is a good place to start if you're on a tight budget).
Best advice I could give you is to start modestly. Don't think big right off the bat. Make a small game or two once you've learned the ropes and see how you fare. Once you gain enough experience you can expand your horizons. Starting with an ambitious project can be very tempting but is a rookie mistake nonetheless. People who do this are often left with an unfinished project that will never see the light of day due to the sheer complexity of all the necessities of it and the grand effort that has to go into the whole thing. Especially if you plan to do it solo. Writing a (good) story takes time and effort. More so putting that story into a (good) visual novel. Plan yo shit well 👍