Layer Transformation Tool lets you edit and tweak your artwork in multiple ways for added convenience.  

Tap on Layer transformation tool icon on the top middle toolbar to bring up a pop-up with a list of transformation options. The layer transformation options available on Sketch Desk are as follows: Freeform, Uniform, Distort, Flip Horizontal, Flip Vertical, Rotate, Fit to scale and Refresh.  

Once tapped on the Layer transformation tool your active layer content will appear within a black outlined bounding box with 4 controllers on each of it’s corners. These controllers will help you resize and adjust your selection however you wish to with the help of layer transformation optioning.