Performance Max, often shortened to PMax, is a Google Ads campaign type that runs across all of Google's channels, including Search, Display, YouTube, Gmail, and Maps, from a single campaign. You provide goals, budget, and creative assets, and Google's automation handles placement and bidding.
PMax can find conversions across surfaces you might not manage manually, but it gives you less visibility and control, which is why an account-level management layer with clear guardrails is valuable alongside it.