General structure

    Properties:
      Tags:
        - Key: "Tag1"
          Value: "TagValue"
        - Key: "CreatedBy"
          Value: "CloudFormation"

Set SSM parameter Store with Tag, with Tag data in Parameter section of Cloudformation:-

Parameters: 
  AccountNumber:
    Type: String
    Default: 1234
    Description: AccountNumber

  TagRepo:
    Type: String
    Default: MyRepo
    Description: My Own Repository  

    
Resources:
  AccountParameter:
    Type: AWS::SSM::Parameter
    Properties:
      Name: AccountNumber 
      Type: String
      Value: !Ref AccountNumber
      Tags:
        Repo: !Ref TagRepo
        CreatedBy: Cloudformation 

Tags for S3 Buckets:-

  LambdaS3Bucket:
    Type: 'AWS::S3::Bucket'
    Properties:
      BucketName: MyUniqueBucket
      Tags:
        - Key: Repo
          Value: !Ref TagRepo
        - Key: CreatedBy
          Value: Cloudformation