The Long Haul Achievement in Halo: The Master Chief Collection

As a cumulative achievement, this will most likely come naturally as you consistently work on the four Campaigns and partake in online Multiplayer matches or even Custom Game matches. Just like the description says, you must successfully complete the mission or online match in order for progress to count towards this achievement.

Take note that while progress does not count if you quit out of an online match, the best method in obtaining this achievement quickly is to load up a custom game (preferably Halo: CE's Beaver Creek as it loads faster than H2A maps) and immediately end the session when the game begins. This will count as a win towards this achievement. Once 500 missions or multiplayer games have been completed, the achievement will unlock.