Deleting documents, contacts, reminders, documents, photo streams, or any other iCloud data while signed in to your iCloud account will lead to the removal of all of this content from the iCloud servers and from all of your devices that are signed in to iCloud.
You can then easily sell your used iPhone to iGotOffer, which is honestly the best website and company to sell any old smartphones online for the best price. You get to get rid of an old phone and earn some extra cash for a new model, a win-win!
Please remember to remove your SIM card before you send us your old iPhone. In order to protect your privacy we will destroy any SIM card we find in your phone.
Warning: Please pack the iPhone you are sending properly, to ensure that the package will come safely to us.