Simply put, it is a way to test two different versions of an online advertisement to see which one is more effective at attracting customers and generating more sales. For example, if you have an online store selling shoes, you may want to test two different versions of an advertisement, one offering shoes at a lower price and the other offering shoes at a higher price. You would then launch both ads online and observe which one has a higher conversion rate (the percentage of customers who go from viewing the ad to making a purchase). An A/B testing plan not only helps you test the effectiveness of your ads, but also gives you insight into what your customers prefer and makes your ads more appealing.