The default Valorant game mode where teams attack and defend is Unrated.
Unrated is Valorant’s standard plant-and-defuse mode. Two five-player teams alternate between attacking and defending, with attackers attempting to plant the Spike at a designated site and defenders trying to stop the plant or defuse the Spike afterward. A team normally wins by reaching 13 round victories.
The mode is called “Unrated” because it uses the core competitive-style rules without affecting a player’s ranked rating. Competitive follows the same broad attack-and-defense structure, but it is a ranked queue with different surrender, overtime, and matchmaking rules. That makes Competitive a common but technically incorrect answer to this question.
Spike Rush also includes attackers, defenders, and Spike sites, but it is a shorter variant with randomized weapons and special power-up orbs. Deathmatch is different entirely: it focuses on individual eliminations rather than planting or defusing. Unrated is therefore the canonical answer for Valorant’s ordinary attack-versus-defense experience.