If you are a buyer's agent, you can't unless the listing agent gives that information to you. We cannot provide information about other offers.
If you're a listing agent, information about each offer submitted on your listings is available by logging into your OfferSubmission.com account.
The seller may opt to request your buyer's "Highest and Best Offer" via a Multiple Offer Notification from our system. This option is only available to the seller if there are actually multiple offers, so be assured that there are multiple offers if you receive this notification.