What output voltage is required for the load? What is the single-phase supply voltage at the service entrance?(208, 230, etc.)?

Whatever 1-phase voltage goes in is what comes out 3-phase. If the 1-phase input voltage and 3-phase load voltage are different, a transformer may be needed. The converter output is ALWAYS 3-wire delta. A 4-wire wye output will require the addition of a delta-wye transformer.