SEPA means Single Euro payments Area
SEPA is therefore an area in Europe where you can pay in one way. So it doesn't matter if you buy something online from the Netherlands or another European country. This is all in the same way. Due to the advent of the Euro, cash payment has become easier in Europe, but there are many different local payment options and systems available online. European politics wants to make the EU a competitive economy, so 1 common method of online payment is important. Now it is often still complicated, or there is a high cost of paying online in another European country, via SEPA this should be made easier. More information on this can be read on the SEPA website.