220v but an adapter plug is required - Amazon have some great multi plugs with the round 3 pin
Public transport is very limited best option is UBER. There is a dedicated UBER area at Cape Town airport follow signs for eTaxi It is reliable, safe and inexpensive. UK uber app works in Cape Town
eSim is cost effective way of international roaming - airalo works well in Cape town and can be used on existing phone via an app
the currency is RAND (zar). The current exchange rate is £1 buys R23 The best travel card I have found is WISE. Their exchange rate is the most favourable. The card is free and valid for 3 years so great to add now whilst is a positive exchange