Notification snooze in BlueMail is the Reply Later feature: marking an email Reply Later snoozes it — it's set aside without being deleted or archived, so you can come back to it when you're ready to deal with it.
To mark an email Reply Later:
- Open an email (or conversation) and tap the overflow (⋮) menu.
- Tap Reply Later.
The email moves straight to the Today column of your Later Board — there's no date or time to pick, and a confirmation lets you know it's been snoozed.