In brief
transform changes the visual coordinate system through translation, rotation, scaling or skewing. For example, transform: translateX(20px) shifts the displayed box.
Useful to know
transform changes the visual coordinate system through translation, rotation, scaling or skewing. For example, transform: translateX(20px) shifts the displayed box. [1]
It does not automatically rearrange neighbours as changing width or spacing would. When overlap appears, decide whether the goal is visual movement or a layout change. A transform can also create a new stacking context.
Sources
For further detail and to check the information: