It depends on what you mean by soft and hard reset. Soft reset typically means a simple reboot--i.e., powering the phone down completely, then turning it on again. As long as you saved any data that you were working on before the reboot, no data will be lost.
A hard reset typically means a full factory data reset, which wipes the phone. This can be achieved from within the
Settings>Backup & reset menu. If you're unable to get there, you can also boot into Recovery and do it there as well:
Reset: Samsung Galaxy S 4 | T-Mobile Support