Why are the photos taken in the photo studio so good that they are only processed by PS? Have you used any other software? How can I make the skin with that effect?

Generally speaking, PS is the main way to process photos.

There are still many hardware problems in completing a series of photos, such as the layout of the scenery designer before shooting, the lighting engineer adjusting the most suitable light, and the photographer will choose a camera with good performance, use professional technology, and then make it professionally later.

In order to produce that effect, it is not enough to use PS alone, and comprehensive conditions should be considered before taking pictures.