In World of Warships there are four different game modes and in each one of them ships of the same or similar tier is recommended as teams are matced based on their highest ship tier.
Random Battles
This is a 7v7 Battle with games designated into 3 sub-categories, these are 'Standard Battle' where your goal is to destroy all enemy ships or capture all bases. 'Nautical Superiority' where your goal is to score 1,000 points before the enemy team by capturing the center area and destroying their ships, and 'Domination' where you goal is to score 1,000 or more points before the end of the round by capturing areas and sinking enemy ships.
Co-Op Battles
This mode is a player vs AI game where the goal is to destroy all enemy ships or capture all bases.
Ranked Battles
In this mode you complete with other players for ranks.
Campaigns
In this mode your goal is to complete various challenges on different levels, this will usually involve sinking enemy targets with a specific ship. When you complete a mission for the first time you will earn Special supply rewards. When you complete missions of higher levels you will win stars and additional rewards. The campaigns in World of Warships Blitz are inspired by historical naval events, the first of which is the 'Battle of Coral Sea' and consists of 5 Normal stages and 5 Elite stages.