You should say:

• Which area it is
• When and where you came to know this area
• How you got information about this area
• And explain why you are interested in this area

Sample Answers: https://ieltsquangtri.com/describe-an-area-of-science-that-you-are-interested-in-and-would-like-to-learn-more-about/

You should say:

• What the rule is about
• What happens when people break the rule
• Why you think it is an important rule
• And explain how you feel about the rule

Sample Answers: https://ieltsquangtri.com/describe-a-rule-that-is-important-in-your-school-or-at-work/

You should say:

• What it was
• How long he or she had this job
• How he or she got the job
• What skills this job needs
• And whether you would like to have this job in the future

Sample Answers: https://ieltsquangtri.com/describe-one-of-your-grandparents-job/