The website I use is called Onshape, it’s really nice because they have vex parts that you can download and port into your projects. There are also a lot of walk-through videos on YouTube I suggest watching first here. I am by no means an expert CADer so I suggest talking to people on this forum post if you want to learn more they know much more than I do. There is also a discord server dedicated to CADing ( I’m not in it I should probably join it) but here is the link. Hope this helps!