Do you need high voltage or current to produce a spark?
You need a high voltage to produce a spark through air.

There are two ways to get a high voltage. One is to make a high voltage intentionally.

The other is that you can get a high voltage unintentionally by breaking a large current in an inductive circuit. As all conductors are inductive to some extent, a sufficiently high current going through an opening switch will create a spark as the contacts open and try to stop the current. Supplying a headlight bulb from a 12v battery via jump leads, and then pulling one away will usually make a spark as the connection opens.