Hi friends, welcome to factorio-realms.com.
Depending on the version you installed. These directories are in the different positions. You can try following directories.
%appdata%\Factorio
%appdata%\Factorio
<your_factorio_dir>
To open these folders quickly, just press Win+R and fill the address above.
If you still cannot found these directories:
Open file location
.~/.factorio
To open it quickly, just open file browser such as nautilus or dolphin, then press Ctrl+L to jump to navigation bar.
~/Library/Application Support/factorio
Original Post: https://factorio-realms.com/tutorials/where_are_factorio_saves_and_mods_located