How to set the default value for specific vocabulary

Problem/Motivation

hi i was looking for how to print page title of taxonomy term when i found this module.

However, i have not seen where to configure the default value for specifics terms of vocabulary.

Even after adding the metatags field to the vocabulary in "Manage fields", checking the default value fields doesn't display any field

Steps to reproduce

- enable the module
- create a specific Vocabulary
- go to metatags settings page to activate the Page heading for the created Vocabulary
- Go to Mange field of the vocabulary and add the metatags field the check the Default value box **no input form displayed to set the default value"

am i missing something
Thanks