A candidate who has experience will know what kind of e-mail is needed for a marketing campaign and would be able to identify where and how the e-mail could be improved.
If you are a fresher you should know the characteristics of a good email to answer this question. See, if the e-mail you are seeing meets the following requirements:
Mobile friendly emails: It is important to create mobile optimized email content that is engaging and appealing on a smart phone. Make sure your content is seen correctly if sent on Gmail or Outlook or on device like the smart phone.
Consider text emails: Email client like Outlook blocks images so it is best to write a good descriptive email with links to your site.
Effective subject line: Looking at the subject line people decide if they should open the mail or not. Make sure your subject line is to the point and make it as compelling as possible.
Email from real person: No one likes an email in which they can’t ask a query back. If your email is only for the information purpose, for e.g., letting the customers know that their product has been dispatched, you can send the system generated email but provide your customers a way in the email to ask a query, if they need to.
Personalized email: The more personalized email you send, the better will be the reply rate/ expected action rate. It makes the receivers believe that someone genuinely means to contact them rather than it being a system generated thing sent to everyone.
Defined call to action: Looking at the email the reader should know what is needed to be done by them. A properly defined call to action can be anything from calling at a given contact number, or form submission or driving traffic to a page.
Is the email list relevant? : You will have an email list with different types of subscribers who are interested in different types of services. Suppose A wants coupons, B wants to attend an event and C wants to get some information. All three have different needs. So it is necessary to understand who you are sending your emails to. Relevant email to correct person will get you higher open rate and fewer unsubscribe requests.