Place of business is the location where a business is conducted, usually at a property premise designated for commercial, industrial or office purposes.
The owner of a sole-proprietorship or partnership is required to notify the Registrar of the principal place of business and any other place where the business is carried out.
P.O. Box address cannot be used as the business address.
(Adapted from Source: ACRA, Business or Company Address)
A registered office address is where communications and notices may be addressed. For a company, the registered office in Singapore must be operational and accessible to the public during normal office hours (Companies Act (Cap 50), S142(1)).