The following are tags supported in the welcome email sent to new members and the notification sent to admins (if enabled under the membership level). The welcome email template is setup under each membership level under Labels & Membership > Membership Levels. The admin new member notification email template can be edited under Customization > Emails.
Note that only fields that are part of the first tab of the Member Sign-Up template can be used because the emails are sent as soon as the member completes the first tab of the form. Therefore not all account fields listed here may be applicable.
[us] - Name of your organization
[website] - Website for your organization (as setup under Organization Settings
[contact] - Contact name field if available, otherwise Account Name field
[nam] - Account name
[ctc] - Contact name
[biz] - Organization name
[pos] - Position
[adr] - Address, formatted as one line, excluding country
[ad1] - Address line 1
[ad2] - Address line 2 (excluding country)
[con] - Address country (2 letter code)
[phn] - Phone
[cel] - Mobile
[fax] - Fax
[eml] - Account email
[emd] - Public directory email
[web] - Website
[sky] - Skype
[cnm] - Tagline
[pfl] - Profile description
[nte] - Admin note
[x??] - Custom field - use the 2-letter identifier (in lower case) after the "x". For example for "LF", the shortcode would be [xlf]
[password] - Password
[label] - Name of membership level
[amount] - Membership level billing amount
[interval] - Membership level billing interval
[billing] - Billing method
[end] - Membership expiration date
[dcc] - Discount code