Explanation

Step 1 : az acr create
An Azure Container Registry (ACR) can also be created using the new Azure CLI.
az acr create
--name <REGISTRY_NAME>
--resource-group <RESOURCE_GROUP_NAME>
--sku Basic
Step 2: az ad sp create-for-rbac
Once the ACR has been provisioned, you can either enable administrative access (which is okay for testing) or you create a Service Principal (sp) which will provide a client_id and a client_secret.
az ad sp create-for-rbac
--scopes
/subscriptions/<SUBSCRIPTION_ID>/resourcegroups/<RG_NAME>/providers/Microsoft.ContainerRegistry/re
--role Contributor
--name <SERVICE_PRINCIPAL_NAME>
Step 3: kubectl create
Create a new Kubernetes Secret.
kubectl create secret docker-registry <SECRET_NAME>
--docker-server <REGISTRY_NAME>.azurecr.io
--docker-email <YOUR_MAIL>
--docker-username=<SERVICE_PRINCIPAL_ID>
--docker-password <YOUR_PASSWORD>
References:
https://thorsten-hans.com/how-to-use-private-azure-container-registry-with-kubernetes