- Start Origin and Login
- Find the Game in My Game Library
- Right-Click on the game and choose Game Properties
- Click on the Tab Advanced Launch Options
- In the field under Command line arguments write -w and press Save
- Start the game
- After starting the game you can set the desired setting in the game and then remove the setting in Origin.
This method only works if the game was already started once and the user folder has the file needed.
Sims 4 has three different Display Types: Fullscreen, Windowed and Windowed-Fullscreen. You can set the mode directly in the Options.ini file