The reset button is typically located next to the thermostat on the water heater. You will want a screwdriver to remove the thermostat’s cover plate so that you can reach the thermostat and its reset button. If you check closely, insulation may be present around the thermostat. In some variants, a plastic cover is placed over the wires near the reset button and temperature dial to protect them. Be aware that while most modern electric water heaters have two heating elements and two thermostats, there is typically only one reset button available.
The owner’s handbook can be reviewed if you need help locating the button to reset the thermostat on your water heater. There should be a labeled diagram of the water heater at the top of the instruction handbook