Provisional tax is a way to pay your income tax during a tax year.
All individual provisional tax payers must submit a provisional tax return (IRP6), and make a payment of provisional tax in August and February each year.
You do not need to pay provisional tax on your salary because your employer deducts the correct amount of tax (PAYE) from your salary, but if you receive any other income which is not a salary, you have to register as a provisional tax payer.
If you were supposed to pay provisional during a tax year and did not, SARS can make you pay penalties on underpayment of tax.