If you have any sensitive data at all — and these days who doesn’t? — at some point you are going to need to find a way to securely wipe it. It’s a fact of life. Here’s a quick guide to securely wiping data off iPhones, iPads, Android devices, hard drives (HDDs), solid state drives (SSDs), and flash drives.
https://www.zdnet.com/pictures/how-to-quickly-and-securely-wipe-your-data-off-almost-any-device/