There is no such thing as a “worldwide" patent, design or trademark registration. Separate patent, design or trademark protection (with few exceptions) has to be obtained in each country of the world in which such protection is required. For example, it is not possible, by way of a single patent, to achieve worldwide protection for an invention. This can be problematic because the other countries in the world also have novelty requirements which have to be satisfied in order for an invention to be patentable there. However, most of the countries in which you are likely to require protection, are members of the so-called “Paris Convention” which is also known as the “International Convention”. The member countries recognise, for the purpose of establishing a priority date, a patent, design or trademark application filed in another country that is also a member of this Convention.
South Africa is a member of the International Convention. Thus, a single patent, design or trademark application filed in South Africa, can secure for you, for a period of twelve months (for patents) or six months (for designs and trademark registrations), an option also to file corresponding applications in other countries such as the United States, the United Kingdom, Japan, Australia, Germany and other European countries, etc.
PCT is an abbreviation for the Patent Cooperation Treaty (which is administered by WIPO). More than 100 countries are members of the PCT. As mentioned above, a single patent application in South Africa gives you a twelve-month option to file a complete specification in respect of those countries in which you might want to exploit your invention. In terms of the PCT, a single so-called “international” patent application can be filed in one of the member countries, designating those countries in which patent protection is required, and then (with few exceptions) you have an additional eighteen months to “nationalise” the PCT application in some or all of the countries you have designated. In other words, filing a PCT International application extends your abovementioned twelve-month option for filing in all of the important countries in the world, to thirty months (ie twelve plus eighteen). A PCT International application can also be filed at the South African Patent Office.