Yes, you can run a heater on 110/120 volts of power, but this is only practical for small, enclosed spaces like garages, indoor work areas, or small outdoor areas (up to about 5' x 5'). A 110/120-volt heater typically has a maximum output of 1,500 watts, which limits its heating capacity.
For larger spaces, running a 120-volt circuit is not ideal because it won’t provide sufficient heat. Instead, using a 240-volt circuit is a more efficient option. With a 240-volt heater, you can heat much larger areas with better comfort, and although it requires more power, it still only takes two spaces in your breaker panel (as opposed to one for a 120-volt heater).
In summary, while 120-volt heaters are fine for small spaces, a 240-volt circuit is much more efficient and practical for heating larger areas.