Sometimes two different figures of a person appear in photography works. Is this post-production?

This is the effect of multiple exposures.

Most Nikon machines have this function. As long as you turn on the multiple exposure function in the menu, and then take two or even three photos according to the settings, the camera will automatically combine them.

Many Canon machines do not have this function and can only use computer software for post-processing.

But whether it is camera processing or post-processing software, they are actually similar.