You can customize the email template for payment/refund receipts for memberships, events, and other under Customization > Emails.
The following are tags supported in the membership, event and other payment receipts. Note that for membership payments only the account fields used in the membership form would be populated. Similarly only the account fields used in the event registration form will be populated when sending event payment receipts, and only the fields used in the forms/carts/donation checkout form will be populated when sending the form payment receipts.
General Tags
[us] - Name of your organization
[website] - Website for your organization (as setup under Organization Settings
Account Field Tags
[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]
Payment Specific Tags
[_id] - ID (unique) of transaction
[txn] - Credit card transaction ID
[last4] - Last 4 digits of credit card if available (credit card transactions)
[method] - Method of payment (card+last4 or other)
[total] - Total transaction amount
[tax] - Tax
[pretax] - Total before tax rules applied (ie. original price/amount)
[lesstax] - Total transaction amount excluding tax
[due] - Payment due (offline billing)
[itemtable] - Table showing items, quantity, price and subtotal - this table cannot be customized
[dcc] - Discount code
[instructions] - Payment instructions (offline billing)
[label] - Membership level (membership only)
[title] - Title (event or form only)
[time] - Date/time of event (event only)
[location] - Location of event (event only)