"Velero CLI tool" is currently referenced in the docs but does not say where to obtain them.

"Velero CLI tool" can be obtained by downloading from

• Github release
• Homebrew - macOS
• Chocolatey - Windows
• Accessing velero binary in velero deployment in the cluster.
  Set alias like

  alias velero='oc -n openshift-adp exec deployment/velero -c velero -it -- ./velero'
  

Accessing velero binary in velero deployment via alias above would not work if your Data Protection Application custom resource does not have a "Reconcile complete" status.

If you are downloading CLI instead of using alias, the velero CLI tool should ideally be of the same version as the velero server running in the cluster.

We publish velero version relationship with oadp here. If this table isn't in the docs already, it should be added be noted there as well at least from 1.0.0 onwards.