There could be many reasons why you wan to reset your Samsung Galaxy S4 but by far the most common reason is the inability of the device to perform certain functions viz. bluetooth, wi-fi etc. In other words when everything else fails to troubleshoot a problem, the reset option helps to fix about 90% of these errors. Just follow these simple steps below to restore your phone back to factory settings. *Please save your data before you do this.
1. Tap on Apps.
2. Scroll to and touch Settings.
3. Select Accounts from the top tab.
4. Touch Backup and reset.
5. Tap on Factory data reset.
6. Read the warning and tap Reset device.
7. Touch Erase everything.
8. The phone will reboot.