Erasing an iPhone or iPad before you part with it
Back it up, sign out, then erase it from the phone itself. Deleting things one by one isn't enough.
What's usually going on
An iPhone that hasn't been erased properly still holds your messages and photos. One that's erased but still linked to your Apple Account is locked by Activation Lock, so the next owner or trade-in program can't use it. The built-in erase handles both if you do it in order.
Worth trying first
Back it up.
Make sure an iCloud or computer backup has finished recently, and that your new phone has everything you need.
Unpair an Apple Watch.
If a watch is paired, unpair it from the Watch app first. It saves a backup of the watch.
Erase from Settings.
Go to Settings, General, Transfer or Reset iPhone, then Erase All Content and Settings. Enter your Apple Account password when asked; this also turns off Find My and Activation Lock.
Sort out the SIM.
Remove a physical SIM card. If it uses an eSIM, you'll be asked whether to keep or erase it; erase it unless your carrier tells you otherwise.
Remove it from your account.
Sign in at account.apple.com, open Devices, and remove the old phone if it's still listed.
When to hand it over
If you can't remember the Apple Account password, the phone is broken and won't turn on, or several family devices are being retired at once. We'll make sure each one is erased and released properly.
Your own technologist, on call.
Tell us a little about your setup. We'll take it from there.