Electric power is measured in watts. It does not matter if it is single phase or three phase. All things being equal, for the same load, the power measured in a single phase circuit or a three phase circuit, will be the same.

All high-voltage distribution systems are three-phase. Single-phase 'spurs' off the main line, supplying, for example, farm houses, are simply two lines of a three-phase system.

Three phase power is a method of electric power transmission using three wires. Three phase power systems may have a neutral wire that allows the system to use a higher voltage while still allowing lower voltage single phase appliances. In high voltage distributions, it is not common to have a neutral wire, as the loads can simply be connected between phases.

The 3 phase electric power is very common way of electric power transmission. Three circuit conductors carry three alternating currents the first conductor as reference the other currents are delayed in time for 1/3 and 2/3 of the cycle of the electrical currents.

No, you cannot get a three phase supply directly from a single phase supply.

Nowadays electronic inverter units can be bought that will do the job. For very low power loads the cost of such invertors is quite reasonable but for high power loads they are very expensive.

For high-power industrial uses the most economical solution is to have a 3-phase service installed by the local electric power utility company.