One of the essential abilities you need to have in Photoshop is the ability to take something that’s 2D and make it look 3D. Adding shadows in Photoshop is easy. The effect is everywhere now and expected in the presentation of most all work.

How to add Shadow Effect in Photoshop

To make it easy, have everything that you want to have a shadow in one layer. Then:
Rasterize layer to have shadow- Do this by right clicking the layer you want to rasterize.

Duplicate that layer- shortcut is “command(or ctrl) J”

Flip layer- go to Edit>Transform>Flip Vertical while the layer is selected.

Position flipped image under upright image using move tool

Choose the select tool

Set Feather- This will effect the level of fade. For High resolution (300PPI) try a high feather around 50 px, For web images (72PPI) start at 10px

Select most of the flipped image

Click delete one or two times

Adjust (lower) opacity to fit