---
Parameters:
    VPCName:
        Type: String
        Description: VPC Name for test.

Resources:
  BasicParameter:
    Type: AWS::SSM::Parameter
    Properties:
      Name: test-VPC-Name
      Type: String
      Value: !Ref VPCName
      Description: SSM Parameter test.
      Tags:
        Environment: Test

BASH to read out parameter:-

VALUE=$(aws ssm get-parameters --names "/path/to/parameter" | jq -r '.Parameters.[].Value')
echo ">${VALUE}< from Parameter store"