https://cdn.ymaws.com/sacap.site-ym.com/resource/resmgr/2023/SACAP_Fees_and_Charges_for_t.pdf

There are no ‘essential subjects’ required for you to study Architecture. However most universities insist that you have a pass in Mathematics.  Art can be an advantage, as can Engineering, Graphics and Design (EGD). Physics can also be informative. 

https://sacap.site-ym.com/resource/resmgr/2023/IDOW_FAQ__004_.pdf

There are various qualifications that a person can take in order to prepare for a career in the architectural profession. These include: a Higher Certificate in Architecture, a Diploma in Architecture, a Bachelor of Architecture (NQF 7) or an Advanced Diploma in Architecture. Should you wish to study towards registration as a Professional Architect, you will then need to proceed to a Bachelor of Architecture (Hons) and a Master of Architecture degree.

A person registered as a candidate prepares building plans under the direction, control and supervision of a registered professional who must take responsibility for the work performed by the candidate. A candidate cannot take responsibility for architectural work, only a registered professional.