To skew an object by using the resize handles
Select an object or a group of objects or anchor points. The resize handles appear.
Position your pointer near but outside one of the side handles and use one of the following methods:
To skew horizontally, drag the top or bottom side handle of the object to the left or right.
To skew vertically, drag either the left or right side handle.
To skew the object around its center point, hold down the ALT key.
A shape (in blue) being skewed with the top handle
You can skew and create a duplicate of a selection at the same time by holding down CTRL+ALT when you drag.
To skew an object by using the Action Bar
On the left side of the Action Bar, click the registration point icon to indicate which part of the selected object you want to stay stationary during skewing. For example, if you want the upper-right corner of your object to remain in position when the rest of the object skews, click the upper-right corner of the registration point icon.
Adjust the Skew Angle . Drag the pointer up or to the right to increase the value, or drag it down or to the left to reduce the value. Click the field to type a numeric value.
To skew vertically (shear) instead of horizontally, set the Rotation Angle and Skew Angle fields to the same value.