i erased an iphone im selling

You, in all likelihood, you will end up with activation lock, and the iPhone will be useless to any party you sell it to unless you give them your Apple ID password.

See Turn off Activation Lock https://support.apple.com/en-us/HT201441See this heading  If you erased your own device It says: "If you don't sign out of iCloud before you put your device in recovery mode and restore, it might remain in Activation Lock. That means you need to enter the same Apple ID and password that … was used when … [the device was last set up].

[Use] forgot your Apple ID or your Apple ID password [to recover the needed credentials if you don't know them.]

If you have iOS 11 or later and your account is protected with two-factor authentication, you can turn off Activation Lock with your device Passcode. Tap Unlock with Passcode, then tap Use Device Passcode."

See the "If you no longer have your iPhone, iPad, or iPod touch" section of What to do before you sell, give away, or trade in your iPhone, iPad, or iPod touch - Apple Support