Auction mechanisms were originally developed to allow crosses (internalization) in the US option market. The incentive given to the regulators were to give the opportunity to retail client to get price improvement on their orders.
For an auction to start, it needs 2 things (simple example cause it may be more complex):
1) A retail order (called Public Customer order)
2) A market participant willing to cross (internalize) that order, meaning willing to take the opposite side of the retail order.
Then an auction is launched for other market participants to submit orders to improve the original retail order. Any remaining quantity left that has not been improved is traded against the auction participant who submit the auction.
There are mechanisms that exists allowing market participant to send their order flow to other participant in order for them to start an auction.
Maybe a link with more details would be helpful:
https://boxoptions.com/about/price-improvement/
Btw, this is the implementation at one exchange. Many other exchanges also support auctions, and they have their own set of rules.