Unlinking iPhones

Hebrews12

I have a few old iPhones that belonged to my daughters which I'd like to sell however, they can't remember their passwords to get into them. They have both removed them from their Apple accounts online so will that be enough to make them useable by someone else?

Also, is there any way that I can wipe them without being able to get into them?  I'd also like to be able to find out what model they are and check the battery health in order to sell them.  I'm an Android user so am a bit clueless with iPhones so any help would be greatly appreciated. 

DullGreyGuy

As long as Find My Phone has been deactivated by them you can follow the instructions https://support.apple.com/en-gb/118430 to do a factory reset without knowing the password.

Hebrews12

DullGreyGuy said:

As long as Find My Phone has been deactivated by them you can follow the instructions https://support.apple.com/en-gb/118430 to do a factory reset without knowing the password.

Thank you.  Is that what they do from their account rather than the phone?