Select the “New to VMware Certifications” option on the left of this page and expand Step 1 for details: https://www.vmware.com/learning/certification/vcta-dcv.html

The training isn’t mandatory though, how you gain the knowledge needed to pass the exam is up to you.

Select the exam under Step 2 of the page above and you’ll find the exam guide which tells you all the topics you’ll be tested on.