Working with Transparency - Adobe InDesign CC - page 448

Note
In addition to applying transparency effects by choosing Object > Effects
and then choosing an option from the submenu, you can select Effects from
the Effects panel menu, or you can click the FX button at the bottom of the
Effects panel, and then choose an option from the submenu.
1. Use the Selection tool ( ) to click the Light Purple-filled vertical rectangle that
covers the right half of the page.
2. At the bottom of the Effects panel, click the FX button ( ) and choose Gradient
Feather from the pop-up menu.
The Effects dialog box appears, displaying Gradient Feather options.
3. In the Gradient Stops section of the Effects dialog box, click the Reverse Gradient
button ( ) to reverse the solid and transparent colors.