You can buy a Fog light kit from Ford part number AMC1BJ 19B532 AB and you will also need to replace the switch assembly D6BT 13A024 BB. Not sure what exactly is in the kit, but the wiring may actually already be there as the instructions of the kit below make no mention of wiring. I can try and find the contents for you and if need be get the kit for you too. I think the WZ kit fits the WT?
https://www.ebay.com.au/itm/GENUINE-...oAAOxy4t1SlprW
WT Fiesta Fog Lamps.pdf