Currency and tax

PO Flow keeps currency simple: a shop-wide default, plus per-supplier overrides where needed.

Default currency

Go to Settings → Purchase Order Defaults and set Default currency. New POs use this currency unless the supplier has its own currency.

Per-supplier currency

Each supplier has a Currency field on its profile. If set, that currency is used on every PO with that supplier, overriding the shop default.

Tax on a PO

There is no shop-wide tax rate setting. Tax is entered as a fixed amount per PO on the PO form, in the Tax field. The PO total is the sum of line totals plus tax plus shipping.