To add tags to an existing Lambda function

The following tag-resource example adds a tag with the key name DEPARTMENT and a value of Department A to the specified Lambda function.

aws lambda tag-resource \
    --resource arn:aws:lambda:us-west-2:123456789012:function:my-function \
    --tags "DEPARTMENT=Department A"

This command produces no output.

For more information, see Tagging Lambda Functions in the AWS Lambda Developer Guide.