importing code files

I often work from diffrent computer and I often mail myself new code verisons.
Sometimes I delete some files of a certain project and then put in the project folder the new files.
Every once in a while it's not working:
clion decides this file is deleted and won't accpet it again,
or it just gets stuck on a certain file verison and won't change a thing even though i put new diffrent files.

is there a way to import files (and not projects!)? or to reload a file?
is there a diffrent way to manage my verisons (without softwares like git, with clion built in options)?