How to save files on two devices?

@skyandsims  Sims 4 doesn't support cloud saving, so you'd either need to manually transfer the saves each time or set up a service like OneDrive or Google Drive to do it for you.  With a service like those, you can set it to sync the Sims 4 folder (the one within Documents\Electronic Arts) between devices; whenever you sign into the second device, the most recent saves from the first one should be downloaded automatically.

If you don't want to use a service, just copy the saves folder from one computer to the other each time you switch.