Sold my old Phone - Didn't delete passwords/wallet

Hi,

I recently sold my old iPhone 7. I signed out of my apple account and deleted all the apps, photo's etc. I didn't reset the phone and i thought as i signed out of my Apple account everything would be ok but i'm realising now after my girlfriend is selling her old phone that after she signed out her passwords, wallet etc were all still visible.

Can you let me know if i had to go into them and delete manually or by signing out of my apple account was that enough?

I'm guessing the advise is to change all passwords?

Thanks,