I just got iPhone 12 used iCloud transfer however my passwords didn't seem to get imported why?

Hello johnfrommuscatine,

We understand that you restored a backup of your device to your new iPhone, using the steps listed here: Transfer data from your previous iOS device to your new iPhone, iPad, or iPod touch

In order for passwords to save, you need to be using iCloud Keychain. They are then synced through iCloud as opposed to in a backup. Here's information on iCloud Keychain: Set up iCloud Keychain

So be sure that it is enabled on both the old iPhone and new to enable the connection through iCloud.

Thanks for using Apple Support Communities!