You can setup email receipts to be sent to users under each form in Forms Carts Donations under the Settings tab. You can also setup email receipts to go out when a particular item is checked out under the item's Receipt tab.
The following are tags supported in forms, carts & donations email receipts. Note that only account fields used on the form's template can be applied.
General Tags
[now] - Current date
[us] - Name of your organization
[website] - Website for your organization (as setup under Organization Settings
Account Field Tags
[us] - Name of your organization
[website] - Website for your organization (as setup under Organization Settings
[uid] - Account ID (if user has account)
[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]
Form/Carts/Donations Specific 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]
[pwd] - Password (if an account created by checkout action)
[title] - Name of form
[total] - Purchase total
[tax] - Tax
[pretax] - Total excluding tax
[due] - Amount due if paying offline
[dcc] - Discount code
[txn] - Credit card transaction ID
[tks] - List of items separated by comma
[tkn] - List of items separated by line break
[rqa] - Form template questions/answers (per form's Form Template tab), in list format
[tqi] - Item questions/answers (item receipts only)
[tqn] - All item questions/answers, in list format
[itemtable] - Table showing ticket names, quantity, price and subtotal - this table cannot be customized
[title] - Name of form
[total] - Purchase total
[tax] - Tax
[pretax] - Total excluding tax
[due] - Amount due if paying offline
[dcc] - Discount code
[txn] - Credit card transaction ID
[tks] - List of items separated by comma
[tkn] - List of items separated by line break
[rqa] - Form template questions/answers (per form's Form Template tab), in list format
[tqi] - Item questions/answers (item receipts only)
[tqn] - All item questions/answers, in list format
[itemtable] - Table showing ticket names, quantity, price and subtotal - this table cannot be customized