Do I need to do anything to my iPhone before sending it to you?

Please delete all personal data from your iPhone, remove any SIM cards, and do a “Total Factory Reset.”
For your protection, it is our policy to destroy any sim cards we receive.

The best is to do a Total Factory Reset.
Go to Settings.
Click on “General” and scroll down right to the bottom.
Select  “Reset”
Then select “Erase all content & Settings.”
You will need to type in your Apple iCloud password, and then your iPhone will “restart” and do a total reset as well as remove itself from your iCloud account.

That’s it!