Multivariate testing uses the same core mechanism as A/B testing, but compares a higher number of variables, and reveals more information about how these variables interact with one another.
In this type of testing, a Web page is treated as a combination of elements (including headlines, images, buttons and text) that affect the conversion rate. Essentially, you decompose a Web page into distinct units and create variations of those units. For example, if your page is composed of a headline, an image and accompanying text, then you would create variations for each of them. Now how long does anyone spend on each of these subunits will determine what is driving traffic on the website and what is not.
In a nutshell, the objective of Multivariate testing is to determine which combination of these versions achieves the highest conversion rate.