If you are new to 3D editing check the Blender tutorials. Blender is a free 3D editing software. Always check the 3D editing tips. When you have to 3D print an object you need to pass serval steps to make sure that the object is whater sealed and ready to print without errors. For that you need to use serval softwares. Check the 3D editing softwares to learn which one to use in any case.