Auto-bidding (sometimes referred to as max bidding) allows bidders to set their “highest limit” on an individual package, and let the system bid for them up to that “maximum” amount without needing to interact with the system as other people start bidding against them.
For example, you could set your maximum bid to $500 for a package. Your initial bid will be the lowest amount possible (let's say $200) for the time being. Now when another bidder comes along and attempts to outbid you at $250, the auto-bid kicks in and brings your bid up to match theirs, and you are still winning (because you bid first). This continues until your maximum of $500 is reached and the other bidder surpasses you, or the other bidder stops bidding against you.
