2FA Confirmation
Use this transactional email when a user requests a one-time verification code. Put the code where it can be copied quickly, state when it expires, and explain what to do if the request was not theirs. Replace the sample security language and support link before connecting it to your authentication event.
Loops
Treat the code as required data
Mark the one-time code as required transactional data, then test the missing-value case before publishing. Keep the code above supporting copy, state its expiry plainly, and leave marketing content out of the message. Include a short instruction for anyone who did not request it, and review the account verification examples.