Halo 2: Anniversary is already out on Xbox One with remastered graphics and audio. The PC port brings more PC-centric features like adjustable FOV and widescreen support.
This Anniversary edition adds the ability to toggle between the original graphics and remastered graphics, including remastered cutscenes.
And yes, multiplayer is included. 7 maps from Halo 2: Anniversary and 25 from the original Halo 2 are included.
Halo 2: Anniversary will be launching on May 12th on PC (Steam, Microsoft Store) and also on Xbox Game Pass For PC. It is part of the Master Chief Collection, which is still being sold for the low price of RM65 in Malaysia. It should be available as a separate purchase as well, like the previously released games.