Certified Kubernetes Application Developer: https://training.linuxfoundation.org/certification/certified-kubernetes-application-developer-ckad/

Candidate Handbook: https://www.cncf.io/certification/candidate-handbook

Exam Tips: https://docs.linuxfoundation.org/tc-docs/certification/tips-cka-and-ckad

Keep the code - DEVOPS15 - handy while registering for the CKA or CKAD exams at Linux Foundation to get a 15% discount.