Use modifier keys to rotate, pan and zoom when dragging a 3D graphic.

3D Rotate...

Mouse down near the center of a 3D graphic and drag to rotate it in 3D. The cursor indicates 3D rotation:

2D Rotate...

Mouse down near the edge of a 3D graphic and drag to rotate it in the plane of the screen. The cursor indicates 2D rotation:

Pan...

Press while dragging to pan. The cursor indicates panning:

Zoom...

Press while dragging to zoom. Drag upward to zoom in and downward to zoom out. The cursor indicates zoom:

Notes
If you change the view of a Graphics3D output and then edit and reevaluate the input, the new output assumes the view of the old output:

Rotate...

Mouse down on a 3D graphic and drag to rotate it:

Pan...

Press while dragging to pan:

Zoom...

Press while dragging to zoom. Drag upward to zoom in and downward to zoom out: