Rather than increasing the geometry of our torus, we are going to use a function called Shade Smooth

Shade Smoothing is a function that modifies how light interacts with an object’s surfaces. By interpolating vertex normals across faces we creat the illusion of smoothness without complicating the geometry of a shape. This technique is particularly beneficial for rounded or organic models.

Simply right-click the object and choose Shade Smooth from the context menu.