This is the most complete reset. It wipes everything, including photos, messages, apps, and account info, essentially making the phone like new. 2. What Happens During a Factory Reset?
This restores system preferences (like Wi-Fi passwords, wallpapers, and privacy settings) to their defaults. No personal data (photos, contacts, apps) is removed.
When you perform a full factory reset, the following occurs: Reset iPhone settings to their defaults - Apple Support