The Telephone field is provided by the Telephone module. It is not installed by default with the standard installation profile, and must be installed through the Extend form.

1. The Telephone field type does not have any additional field level settings that are used across all bundles.
2. Click on Save field settings to customize the field for this specific bundle.
3. There are no further settings for a Telephone field instance. This field uses the HTML5 telephone input, which will leverage browser input validation.
4. The field formatter for a Telephone field allows you to display the telephone number as a plain text item, or use the tel:link with an optional replacement title for the link.