Through the initial installation of Uplay PC client on your computer, all files are saved here:
C:\Program Files (x86)\Ubisoft\Ubisoft Game Launcher (default destination).
Please open this folder. If you’ve chosen to install Uplay in a different folder, please go to that alternative destination and open the folder.
Here you find the savegames folder with all savegame files for your account(s) and game(s).
Copy this savegames folder and paste to the install folder on the other computer you want to use for gaming, log in to your Uplay account and you can continue from where you quit the game(s) the last time.