For which reason should parentheses be used?

To make an important point
To provide additional context or clarification
To provide essential information
To indicate a blank space

Parentheses should be used to provide additional context or clarification, and to provide essential information. They are typically used to include extra details or explanations that are not necessary for the main sentence but can provide further understanding. Parentheses are not used to indicate a blank space, as that would usually be indicated with an ellipsis (...) or a dash (-).