How you want Meta to manage your bids in the auction. Lowest cost means maximize results for your budget. Cost cap means hit a target cost per conversion. ROAS target means deliver a specific return. Each approach has different use cases depending on your goals and constraints.
Bid strategies are a divisive topic in digital advertising. Different advertisers swear by different tactics as the one true strategy that all others must follow, but the truth is people have made all of them work. You just have to find the strategy that works for you.