Missions are a game mechanic in Critical Ops where a player can complete tasks for orange credits to unlock a selected amount of skin cases to get a randomized skin in one tier for a randomized weapon. This is not like tokens where the player can choose and buy whichever skin they would like.
A player can view their missions by clicking on their profile from the home menu then clicking on "Daily Missions" or by accessing the game menu during matches.
A player will be given one optional task per day and up to three tasks, usually for a simple mechanic, such as killing an amount of players with a specific weapon or defusing or planting the C4. Once a task is complete, the player will be awarded an amount of credits. On mobile, the player will be given an option to collect the credits initially offered, or boost the amount by watching an ad. This will not work if the player has watched the ad limit.
The player will be given an option to skip a mission for a different one, but can only skip a mission once a day and with no credit reward. The reward amount after skipping may decrease or increase.
Tips for completing missions quickly depends on the task. If you need to get kills with a specific weapon or get headshots, then go into a deathmatch. Try to find a location that suits your weapon (sniper rifles for long range distances, shotguns for tight spaces, etc.) and find where the enemies spawn. Be cautious; don't recklessly charge into a horde of enemies.
If the mission requires you need to plant/defuse the bomb, then all you have to do is simply plant/defuse the bomb. You will make progress in the mission, as long as you successfully plant the bomb, even if your team loses. It is recommended to attempt to plant/defuse near areas covered by your teammates, as they will offer some protection.