One of the advantages of Mailbox only working with Gmail is that a lot of the conventions you’re already used to are present in this fantastic on-the-go email app for your iPhone. If you spend a lot of time on your iPhone using Mailbox, you might have wondered what it does with your mail when you archive, set to later, or add to a list.
Well, it’s really quite simple.
When you launch the Gmail web client after you’ve used Mailbox for the first time, you’ll see a new set of labels on the left side of your Gmail web client, cleverly titled [Mailbox]. There’s a little disclosure triangle to the right of this new label, which will reveal more sub-labels below that, titled “Later,” “To Buy,” “To Read,” and “To Watch.” Whenever you add a List to Mailbox, it will appear here, as well.
When you Archive an email in Mailbox, it can be found in the All Mail section of your Gmail client, and anything you delete will go right to Gmail’s Trash folder.
Any mail you’ve marked as “Later” in the Mailbox app on your iPhone will go to that label in Gmail, and anything you’ve sent to a specific list will show up under that specific label, letting you use the Mailbox workflow when on the go and still access your email from your Mac. It’s all terribly consistent and convenient. The Mailbox folks say that these will also show up in Apple’s Mail as well as Microsoft Outlook, too, but as I don’t use either one, I didn’t have a way to check.
Source: Mailbox App