The only thing a bidder can respond with directly from the bid invitation email is their intent to bid. Best practice is to have each of your bidders sign in and create a password to submit their bid in Procore. That way, their bid is automatically logged from the Planroom into the Bidding tab where you can then transfer to the Commitments tab when you have selected a winning bid.
If they simply email their bid to you, you will have to manually enter in each bid into the Bidding tab. Furthermore, if your bidders don't sign in to access the Planroom, they won't have access to the bid package other then the bid documents that are attached to the email, which may cause unnecessary stress on both ends.