Because different countries use different tax systems, there is a chance an amount you received could be taxed twice.
The possibility of this is often lessened by Double Taxation Agreements (DTAs) between South Africa and your country of residence. These DTAs are international agreements contracted between countries to deal with the potential competing taxing rights against the income of the same taxpayer.
Foreign Residents residing in countries that have DTAs with South Africa qualify for a reduced dividends tax rate. In order for shareholders to qualify for this reduced rate, shareholders need to sign and complete this form declaring that they are foreign citizens and they qualify for a reduced dividend tax rate in terms of a Dual Tax Agreement between their country and South Africa.
If you are unsure if your country has a Dual Tax Agreement with South, you can use this Summary of DTA Rates table, provided by SARS as a reference point.