Transformations refer to a number of operations that can be performed on a selected Object or Mesh that alters its position or characteristics.
Each object can be moved, rotated and scaled in Object Mode. However, not all of these transformations have an effect on all objects. For example, scaling a camera has no effect on the render dimensions.
Basic transformations include:
These three transforms are the three big ones. However, more advanced transformations can be found in the Advanced Transformations section.
For making other changes to the geometry of editable objects, you should use Edit Mode.
Once you have added a basic object, you remain in Object Mode. You can switch between Object Mode and Edit Mode by pressing Tab. The object's wireframe should now appear orange. This means that the object is now selected and active.