2 mail questions from a new apple person

1. The delightful sound made when i sent mail just up and stopped. How do i get it back?

2. How do i keep a note in the Notes mailbox without it also being in my Inbox, where i don't want it to be, but when i trash it from the Inbox it also disappears from the Notes mailbox. I want it in 1 place only and that place is the Notes mailbox.