A subject line in email marketing is a headline that presents a short description of the main content of your email and it does its best to compel the recipient to click your email.  A subject line is primarily seen next to your recipient's name in thier email inbox.  Hence care must be taken to design and draft the subject lines every time you send them so your open rates improve much to your satisfaction. 

A good email marketing platform helps you in drafting subject lines with the aid of AI.  AI-driven subject lines pave the way for successful promotion of your product or service.  Powerful subject lines ensure recipient or prospect engagement.  Strong subject lines have the innate power to take your business to the next level.