how to write deployment yaml file for kubernetes code example

Example 1: deployment example

apiVersion: apps/v1
kind: Deployment
metadata:
  name: nginx-deployment
  labels:
    app: nginx
spec:
  replicas: 3
  selector:
    matchLabels:
      app: nginx
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.14.2
        ports:
        - containerPort: 80

Example 2: kubernetes get deployments

# Get pods in default namespace
kubectl get deployments

#Get Pods in my-namespace
kubectl get deployments -n my-namespace

#Get Pods in all namespaces
kubectl get deployments --all-namespaces