You're over-thinking things....
For one, in most countries 3-phase is typically delivered as a wye connection with a center Neutral connection - not delta. However, that also depends on the local power loads. Wild leg or high leg grounded delta is usually only found where most area loads are single phase.

What country is this in? How power is distributed varies between countries and even between regions within a country.
What voltage is your typical wall outlet at home? 110v or 220v?
ref https://en.wikipedia.org/wiki/Three-phase_electric_power

If you want 208-240v 3-phase power, and if the location also needs a lower voltage for wall plugs & lighting just tell the utility that. They will decide on the type of transformer used as it all depends on how they distribute power in the area where you are.