There are multiple resets you can do on your phone such as soft, recovery and factory.
A soft reset can be done if you're experiencing problems with Apps or if the phone is running slow.
To complete a soft reset on the S42 / S42 H+, press the power key down for 15 to 20 seconds and the device will restart.
Note: A soft reset will not remove any data.
Please be advised that Recovery Mode is not available on the S42.
Backup the device before performing a Factory Reset as this will remove all data and downloads from the phone.
1. On the Settings screen, tap System > Reset options > Erase all data (factory reset).
2. When prompted, tap Erase all data, and then tap Erase all data again. The device will reset to the original factory settings, and then restart.
Note: Resetting your device does not erase any system software updates that have been downloaded or any files on a microSD card, such as music or photos.