WeChat.Template.api_add_template

You're seeing just the function api_add_template, go back to WeChat.Template module for more information.
Link to this function

api_add_template(client, template_id_short)

Specs

api_add_template(WeChat.client(), template_id_short :: String.t()) ::
  WeChat.response()

获得模板ID - 官方文档