You can customize the event confirmation email under the event's Advanced tab. The event payment due invoice is an email that is sent out to your event registrants who select the offline billing option, if offline billing is allowed under the event's Advanced tab. The event payment due invoice template can be found under Customization > Emails.
The following are tags supported in custom event confirmation emails and the event payment due invoice. Note that only account fields used on your event registration form template can be applied.
[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]
[time] - Event date/time
[location] - Event location
[total] - Purchase total
[tax] - Tax
[pretax] - Total excluding tax
[due] - Amount due if paying offline
[dcc] - Discount code
[txn] - Credit card transaction ID
[tks] - All ticket names/quantity on registration, separated by comma
[tkn] - All ticket names/quantity on registration, separated by linebreak
[tki] - Name of ticket specific to sub-registrant
[tqn] - All ticket questions/answers, in list format
[tqi] - Ticket questions/answers specific to sub-registrant (blank if there are no questions are associated with ticket) - limited to 1000 bytes, text will be truncated if limit exceeded so this tag should only be used for short questions/answers
[rqn] - Event registration questions (on the event's Registration tab), in list format
[rqa] - Event registration questions including questions on Customization > Event Registration and Registration tab of event, in list format
[itemtable] - Table showing ticket names, quantity, price and subtotal - this table cannot be customized
[tktqtyamtsum] - Rows with columns ticket name, quantity, price, subtotal*
[qec] - Event check-in QR code
* This tag will break down the tickets into separate rows, with the columns indicating the name of the ticket, quantity, price of ticket, and sub-total. This tag can only be used when working directly in HTML (using the "Source" mode of the editor) as it must be wrapped within a HTML table like this:
<table>
<tbody>
<tr><th>Ticket</th><th>Quantity</th><th>Price</th><th>Subtotal</th></tr>
<tr><td>[tktqtyamtsum]</td></tr>
</tbody>
</table>
CSS should be applied to the table and th elements using inlined rules. Note that CSS cannot be applied directly to the tr or td parent elements containing the tag.