Promotional and transactional/operational emails

Hi @yakshisharma, a promotional/marketing email is an email where the copy is selling or marketing something (product, event, service, etc). People need to be able to opt out of marketing emails. Some examples of these are: 

• Product offerings
• Event invitations
• Newsletters
• Nurture emails

Per this documentation, a transactional/operational email message is part of a transaction that a lead has initiated and you are responding to. Operational messages should not contain any marketing content at all. When you mark an email as Operational in Marketo, the email send will ignore a record's Unsubscribe or Marketing Suspended status. Use the Operational setting for critical emails and auto-responders. Below are some examples of operational messages:

• Receipts for purchases
• Registration confirmations
• Download links in response to form fill-outs
• Requested assets (whitepapers, spec sheets, etc.)
• Product service updates (Downtime notifications, Changes to terms of service, Recall notices, End of service notifications)

Some additional documentation: 

• Here is a blog post that discusses the use of Operational emails and programs in Marketo. 
• Here's the product documentation on Making an Email Operational.
• Here's another thread that discusses the fine details between transactional and operational emails.

Hope this helps,
Katie