A call to action (CTA) is a directive to let your readers know what they should do next. The call to action is an essential step that instructs your readers how to act. Without a compelling call to action, you have no way to convert your readers to the next stage in the buyer's journey.

In display advertisements, the CTA typically leads to a landing page. This is because a display advertisement isn't generally informative enough to persuade to buy or submit an email address. The landing page acts as a "next step," where you can further inform, educate, and influence. 

The best call to action for display advertising tends to have one or more of the following three traits:

1. Describes Benefits or Answers Objections

This type of CTA tells the reader what they will get when they answer the call to action.

It's like holding out a carrot for the reader. "Perform this action, and this is what you'll get!" There's no mystery or wondering about how they will benefit. The reward is straightforward and clear. Examples of this type of CTA on display advertisements include:

• "Get Your Free Book"
• "Claim Your Discount"
• "Free Trial | No Credit Card Required"

2. Fill in the Blank

This CTA trait is wording that you create that describes what you want your reader to be thinking or feeling. It should finish the sentence, "I want to…" Examples of this kind of "fill-in-the-blank" call to actions are:

• LEARN MORE
• SIGN UP
• BOOK AN APPOINTMENT

In most cases, the CTA should be three words at most; the shorter and more punchy the line is, the better. Remember that this is for display advertising with limited size constraints, so the shorter your CTA, the larger your font can be.

3. Meet or Exceed Expectations

The final trait of an effective display advertising CTA--and one that is essential for conversion--is to meet expectations. For example:

• The CTA "Learn More" should go to an informational page
• The CTA "Sign Up" needs to go to a signup page.
• The CTA "Book an Appointment" should go to a calendar app for booking.

Never confuse your reader with more choices or contradictions once they act on the CTA. For instance, the CTA "Book an Appointment shouldn't link to a product or service page.

Display advertisements have more than just a CTA. If you can't integrate the benefits or answers to objections trait, ensure that is included somewhere in the display advertisement. CTAs must always meet expectations or conversions will plummet. The best CTAs describe actions from the perspective of the user (“I want to…”). This covers the basics of what you need to know about CTAs in display advertising. However, there are always more advanced techniques to deliver high-converting CTAs.