Always include a copy of the purchase invoice with the hardware!
Before you can bring a Mac (iMac, MacBook'Pro/Air', MacPro) to a repair center you must remove a firmware password
if it's configured.
Also be sure to make a backup before you turn the device over to the repair center.
Before you can offer an iOS device (iPhone, iPad, iPod, Apple Watch) to a repair center you must perform 3 important tasks.