I've got a rule set in my Apple Mail app to move email older than 90 days out of my inbox to a separate local mailbox (to free up some space on my server – I use imap).
My inbox rule is
If [all] of the following conditions are met: Account [My Main Account] Date Received / Is Greater Than / 90 days Perform the following action Move Message to mailbox: [My Local Backup Mailbox]
That works well, but I want to do the same for sent items.
I can't see any rule options that affect the Sent items folder (or any other specific mailbox for that matter)
I'm on El Capitan 10.11.6