The value of Key depends on the operation that you want to perform:
Add a tag to a health check or hosted zone: Key is the name that you
want to give the new tag.
Edit a tag: Key is the name of the tag whose Value element you want to
Delete a key: Key is the name of the tag you want to remove. Give a name to a health check: Edit the default Name tag. In the Amazon
Route 53 console, the list of your health checks includes a Name column that lets you see the name that you've given to each health check.