What are the differences between 2D and 3D Game Setup

I just want to know what would be the difference if I click 2D game project or 3D game project at the beginning. Can I create 3D world even if I choose 2D ? I clicked on the 2D Toggle View and the scene turned out to 3D. Does it mean I can make 3D project ?

go to this page in the unity manual to find out information about unity’s templates. https://docs.unity3d.com/Manual/ProjectTemplates.html
I am also pretty sure you might be able to make a 2d game In a 3d game, but it is less complicated to just pick the template around what game you are making.