If you want to completely remove all the data from iPhone, then you can use the iOS Data Eraser. iOS Data Eraser, as its name implies, it is a data erasure software service for the iOS device. It can permanently delete all the data in the iOS device, including iPhone 7 Plus, iPhone 7, iPhone SE, iPhone 6S, iPhone 6, iPhone 5S/5C/5, all models of iPad Pro, iPad Air, iPad mini, iPod touch 5, iPod touch 4 and so on. Once you use it to remove data from your phone, you will not be able to use any measures to restore them. This is permanent. And it has a simple operation; you can easily use it to achieve your purpose. It also has 100% security, no one can view your phone data.
Preparation: You need to download the software on your computer and prepare a USB line.
Steps to Permanently Erase All Data from iPhone
Step 1. Connect iPhone to the your computer
After you installing and running the program, you can see all the features from the main interface. Find and click "Full Data Eraser", and then use the USB cable to connect your iPhone to your computer.
Step 2. Start erasing iPhone permanently
When the program recognizes your iPhone, you need to click "Erase" to enter the next step. Then, the program will pop up a window, you need to enter "delete" to confirm your operation and data delete officially started.
Step 3. Wait until the data erasure is complete
When the program starts deleting your phone data, make sure that the connection between the phone and the computer is normal. All you have to do is wait for the process to complete.
When the data is erased, the program shows that the "Erase completely. All data has been erased". Now you can exit the program and get a brand new iPhone.