This is from Steven one of our programmers:
First, for image quality I recommend going into the CoH2 options and setting the resolution to as close as your monitor resolution, if your computer can handle it.
In Steam, right click Company of Heroes under the My Games list on the left, select properties, and click the SET LAUNCH OPTIONS… button.
Paste in
-window –fullwindow
And press enter.
Next time you run the game, it will run in borderless fullscreen windowed mode.
There’s also several other launch options that most users don’t know about.
-nomovies
Skips the into scenes so you can start playing faster.
-forceactive
Makes sound continue to play in the background, so if you alt tab while automatching, you know when you’ve been matched by the sound.
-lockMouse
Makes it so that your cursor is “locked” into the game screen. Very useful for multi monitor setups so you can still use edge scrolling
I personally run with all of the following:
-nomovies -window -fullwindow -forceactive -lockMouse