In this tutorial, I am going to teach you simple effect which enables you to make page curl effect easily.
First of create a new photoshop file with default size and Transparent Background. Import the image that you want to apply page curl effect.
Once the image is loaded select the area where you want to apply page curl effect using marquee selection tool.
After selecting with marquee tool, go to Edit > Free transform (Ctrl+T).
Right click on your selection box and choose Warp.
After selection you’ll see the following change (Grid with six boxes).
Tweak and move vertices until you are satisfied.
Once you get your desired result, press enter.
And you are done with this simple page curl effect using Warp tool.