When we are writing about certain topics, such as the person we should write what we know. What is the truth and not make others damaged. Therefore, we should have knowledge on the subject, we write.
When we write about something like a person, place, and we should write what we know. What is the truth and not to harm others. So we should have some knowledge of what we wrote.
When we write about something such as the person places we should write what we know. What is true and don't make others damaged. So we should have knowledge of what we write.