What is the primary objective of external financial reporting ?

Main focus is to comply with government regulatory authorities.

For prospective  Investors so that they could know that position of the company and consider investment with the company. 

According to me,

Financial reporting should provide information that is useful to present and potential investors and creditors and other users in making rational investment, credit, and similar decisions.

As per my understanding, below are the main objectives for external financial reporting:

1. For common public to know the performance of the organisation and thereby take decision whether to invest or not.

2. For government to review the financial stability, growth, etc of the organisation.

3. For the government and the public to know the contributions made by the entity to the public as a whole for e.g. Common Social Responsibility projects, pollution control initiatives, etc.

provide information to external users 

primary objective is to fulfill the requirement of Security exchange commission requirement.