You can use following smart tags while modifying the email subject and contents:
{{username}} – Username of the registered user.
{{user_pass}} – Password of the registered user.
{{first_name}} – First Name of the registered user.
{{last_name}} – Last name of the registered user.
{{description}} – Bio of the registrered user
{{nickname}} – Nickname of the registered user
{{user_url}} – Website/url of the registered user
{{display_name}} – Display name of the registered user
{{email}} – Email of the registered user.
{{blog_info}} – Name of the website.
{{home_url}} – URL to the website.
{{email_token}} – Token genereated for email confirmation.
{{all_fields}} – All form fields filled by user.
For advanced fields, you can also use a smart tag using field name. e.g. To email country content use smart tag: {{country_1528783674}}
