helm repo add jetstack https://charts.jetstack.io


Install CRDs
(option 1) manually:
kubectl apply -f https://github.com/jetstack/cert-manager/releases/download/v1.7.0/cert-manager.crds.yaml

Or
install with helm
--set installCRDs=true

helm install cert-manager jetstack/cert-manager --namespace cert-manager --create-namespace --set installCRDs=true